Here are some of the must-have apps I've seen for your Blackberry. Why Google has such inconsistent links is beyond me!
Google Search
Visit google.com on your mobile web browser, or go straight to http://www.google.com/m
Google Talk (Chat with co-workers)
http://www.blackberry.com/GoogleTalk
Gmail (Check your personal email)
http://m.google.com/a
Google Maps (Get directions on the fly)
http://www.google.com/gmm
BlackBerry Push Weather
http://mobile.blackberry.com/mss/category_push
Berry 411
Wireless Link: www.thebogles.com/berry411.jad
Desktop Link: www.thebogles.com/Berry411.htm
The best White Pages and Yellow Pages search software for the BlackBerry, this also has a built-in bonus of movie showtimes lookup and weather lookup!
And here are some others you may find interesting:
Spider Solitaire
Free Solitaire game that can be found on the free game download area of the mobile.blackberry.com
The Bible - American Standard Version for BlackBerry
http://www.handango.com/blackberry/PlatformProductDetail.jsp?siteId=1181&osId=950&jid=812D7CF7X7F219ECA4981359737B72FC&platformId=5&productType=2&productId=161699§ionId=6530&catalog=40&topSectionId=-1
Great List of Apps
http://home.comcast.net/~tamsterra/OP/MustHave.htm
http://www.howardforums.com/archive/topic/839591-1.html