Trillian Pro

Buying Trillian Pro is the hardest task you'll encounter with this application -- you can only pay via PayPal for now. Trillian Pro installs in just a few moments, and if you're upgrading from an earlier free edition, the program will retain all your IM accounts and contacts. The new version sports a more colourful interface, but like the free version, it's still skinnable, meaning you can download and install various new looks and themes.

Impressively, Trillian Pro consumed just 5MB of memory on our test Windows XP Home Edition system -- only about 1MB more than the regular version. By comparison, AIM uses about the same amount, while the full version of ICQ uses about 6MB.

Trillian Pro includes plenty of enhancements and features -- more than enough to justify the asking price. Our favourites include the new Metacontacts, a high-level list that represents all the IM services your correspondents use. If Kathy uses MSN, ICQ, Yahoo and AOL, for instance, you can see on the Metacontacts that she's online, and on which service or services. Trillian Pro also offers a tool called Word Matching. You can list and define certain words; then, when one appears in a message, Trillian can highlight it for emphasis, automatically insert a replacement (great for deciphering wacky nicknames that friends sometimes use), or even pop up an alert.

But Trillian Pro's sweetest enticement is its new plug-in feature. To give Trillian more functionality, you can download small, free add-ons that provide a variety of services -- including notifying you of new mail in your POP3 accounts, grabbing headlines from news feeds, and even integrating a Winamp toolbar for fast access to tunes. So far, Trillian Pro offers only nine plug-ins (check them out on Cerulean Studios’ site), but we're eagerly awaiting more.

Security, always a concern in instant messengers, isn't much better in Trillian Pro than in its free sister software, but the service adds 128-bit encrypted messaging when you chat with other Trillian users (free or Pro) over AOL and ICQ. As with previous versions, Trillian Pro still has trouble both sending and receiving files across a firewall, so you may have to manually tweak your router or software firewall to get Trillian to properly transfer files. Corporate users, unfortunately, might never succeed.

What else does your $25 (~£16) buy you? Support. Trillian Pro comes with a year's worth of updates and gives you access to email technical support as well as the excellent user-to-user message forums. The online help is a bit spotty and not sufficiently detailed, but the message boards provide thorough answers nearly every time. To test the new email support for paying customers, we asked for help with one of the new plug-ins and got a spot-on answer within 12 hours.

For anyone who lives with instant messaging all the day long, Trillian Pro's asking price is a bargain. It has a few kinks to work out, but for connecting to friends on more than one service, Trillian Pro is the best. Casual IMers, though, will find plenty of satisfaction with the still-free Trillian 0.74.