Congratulations and welcome to Crackberry! Be sure to check out the BB Help section on this site, it will teach you everything you need to know about your BB! Enjoy!
Check out the BlackBerry 101 How-To Lecture Series ! This will help you with the basics such as downloading apps, themes, wallpaper, ringtones. It's also a good idea to browse the forums and read as much as possible. Many questions you have are answered there already!