Google just released a new interface for the iPhone/iPod Touch that lets Google Apps users easily access everything they need in an integrated environment. This new interface lets you use applications like Gmail, Google Calendar, Google Docs and other services that aren't associated with Google Apps like Google Reader, Google Notebook, Google News and Blogger.
If you have Google Apps for your domain, you can bookmark or set http://www.google.com/m/a/your-domain.com as your default page for quicker access to the information you find the most useful. This specific functionality is new, but the interface you will be using is actually a few months old. With regards to the interface, Google also announced today that it is now available in several languages. Since Google knows that mobile internet is going to be a big thing in the future, they have been increasing the amount of time and resources assigned to work on mobile related products.
The mobile interface for Google (be it using Apps or not) works great. I find that I use my iPod Touch to keep on top of daily routine tasks -- then I use my laptop to do the heavy lifting. The majority of my time online is research, and who needs to use a real computer for that when the iPod/iPhone alternative is quicker, and is far more mobile?