Crackberry.com is an excellent website dedicated to Blackberry users. There is a help and discussion forum, a download section with tools, wallpapers, ringtones, etc., a reviews section, a blog and even a store.
Crackberry.com is a must visit for every Blackberry phone user.
The Blackberry Owner's Lounge is an excellent resource for Blackberry users. The lounge is divided into different sections including Downloads, Tips & Tricks, and Useful Information. To become a lounge member simply you will need to own a Blackberry phone as the signup process asks for a number off of your phone. Click here to go to the lounge.