Tube Map

Unlike some other London Underground maps, Tube Map doesn't need a Wi-Fi or data network to keep you on the move.

It offers directions and departure times of the next Tube trains. Plus, it will give you information about surrounding stations, such as whether that location is open or closed, or running a disrupted service.

However, unlike some other apps, there is no bus direction details integrated into Tube Map. You can get that information by downloading its partner app, Bus London.

Hail-O

If taking a bus to the glamorous Olympics events isn't really your style, a London taxi might be the answer.

Hail-O (shown above) helps you to get a London black cab without furiously waving your arms at passing cars.

Fire up the app, grant location permissions, and it will show your position on a map. Simply select where you want to be picked up and confirm the booking, you can then track the black cab as it makes its way towards you — meaning there's no need to hang around on street corners, wondering if it's on its way.

You can choose to pay by cash or by using a card stored on the app, and it lets you leave a tip, if you like. It also displays a 'call' button, so you can talk to the driver, if needs be.

GetTaxi

GetTaxi performs pretty much the same job as Hail-O: it allows you to hail a black cab from the surrounding area in just a few minutes, delivering booking confirmation SMS messages and tracking the driver's progress in real time.

It also has a points-based loyalty system that can be redeemed against future journeys.

The committee organising the Olympics and Paralympics has produced two official apps, designed to keep people abreast of all things related to the Games.

Official Results

The Official Results app, as its name suggests, will deliver all the gold-medal winners in all sports direct to your phone or iPad. It'll also have Games-related news stories, provide a schedule of events and let you to set reminders for specific events in the 'My Games' section.

Join In

The Join In app, the second official LOCOG title, offers some of the same information, such as the events schedule. However, it also includes other pre-Games features, as well as information about the surrounding area that is not as closely tied to the Olympics and Paralympics.

In the run-up to the Games, it also displays related information such as the live progress of the Olympic and Paralympic torch relays.

If neither of the official London 2012 apps quite hit the spot, you can always keep up to date with the BBC's Olympics app. With the broadcaster's app, you'll also have the option of 24 live streams covering the events, which can be viewed over Wi-Fi or 3G.

Data Usage Monitor

If you do decide to stream those events live over 3G, or have a particularly heavy social media and web-browsing habits, you'll probably want to keep track of how much data you're consuming to make sure there are no nasty surprises waiting in your phone bill when you get home.

One free app that can help you do that is Data Usage Monitor (pictured).

This tool keeps track of how much data you use on your device within a certain time period. It then shows how much data is left of the monthly allowance.

Other features are quick access to a speed test and a breakdown of exactly how much data has been used on a particular day, or in a specific month.

There is also a link to the location where you were when the data was consumed on each day.

DataMan Pro

If you're willing to pay 69p, you can get a few more features with DataMan Pro.

This app enables push notifications to alert you when you exceed or come close to exceeding your data limit. It also shows you how much of the data you've used was consumed on a Wi-Fi connection.

Wi-Fi Finder

If you do exceed your data limit, help is at hand in the form of Wi-Fi Finder.

The app shows at a glance all the closest public Wi-Fi networks around you. But if you want to save your data allowance, you can download the offline database of public hotspots before you leave home.

The database covers hotspots in more than 100 countries, meaning it will be useful long after the medals have been handed out.

Boingo Wi-finder

Boingo Wi-finder is an alternative, if you find yourself struggling with the Wi-Fi Finder app. Don't be put off at first sight when met with an account login screen and no option to create a new account — I entered random characters and hit return, and it loaded the app.

However, it's a little slower to navigate and update than the Wi-Fi Finder app, so I'd make that my first port of call.

XE.com

If you're visiting London from abroad, there's a pretty good chance that the XE.com currency converter app for the iPhone (or iPad) app will also come in handy, particularly when trying to work out exactly how overpriced that sandwich and drink are.

As you'd expect, it'll convert almost any currency into pounds sterling. It also has a useful way of caching the latest rates, so you can do conversions even without being connected to a data network.

Restaurant apps

If at the end of the Olympic day you need to arrange a respectable bar or restaurant for a meal with a client (or the family), then there are plenty to choose from, and plenty of ways to find one.

That said, this was the hardest category to find a free app with useful features. So if you are really fussy, it could be worth investing in something like The Good Food Guide or the AA Restaurant Guide. But if your needs are a little more easily satisfied, then check out free alternatives such as Urbanspoon (pictured), the Mobile Food Guide Lite or TopTable.

All these apps will allow you to find a restaurant by cuisine. In some cases, they let you make a reservation from within the app.

For example, Urbanspoon lets you find a restaurant by cuisine, price or location. Once you've identified somewhere you like, you can read reviews and see more information from within the app.

It also has an option to show only restaurants in the 'most popular' section. However, it doesn't allow you to book a table from within the app.

Top Table, while a little slower for me, does let you book a table at your chosen time from right within the app. It'll keep track of all the bookings you've made in advance, too.

It provides the usual suspect of search parameters for finding a restaurant: name, location or postcode. There's also an option for searching for restaurants near you, or places with special offers.

London Music Mapp

If all the Olympics excitement gets too much, perhaps you'll want to take your interests elsewhere. After all, London is probably better known for its music heritage than its sporting prowess.

London Music Mapp's creator promises it will help you do just that by showing you "new locations you never knew existed, where legendary artists once lived and played, or where great albums were recorded and the music played live for the first time".

It'll also give you details of places and streets referenced in songs, as well as listings for London's concert halls, clubs and other live venues.