Agile Messenger
Agile Messenger is an Instant Messenger for your mobile telephone. Agile Messenger supports the four most popular instant messaging services: ICQ, AOL, Yahoo! and MSN. Highly recommended!

ChatClient Lite by Markus Halttunen
Thousands of simultaneous users, list of current users, log of previous messages, targeted messages, private message and muck more...

Google Maps
Detailed directions, integrated search results and satellite imagery.

Mobile DC by Vakum
A Direct Connect Client. Features Mainchat, PrivMsg, Userlist, Notepad, Favhubs, Search, Hublist. (No P2P atm).

News Reader by Alan Robinson (Symbian)
The application allows you to browse Usenet newsgroups on any UIQ phone, including any attachments which are uuencoded (as opposed to MIME).

Opera
Get the full Internet on your phone. 14 days trial.

Putty by Robert Horvath
SSH-client

Quirc by Bowman
IRC-client

smart2go by Nokia
Load maps from around the world. Discover interesting places with ease, highlight them and get the route.

WebViewer by Reqwireless
Reqwireless WebViewer is an HTML Web browser. Commercial.