You can access the Blackberry 101 Lecture Series on the CrackBerry site, i.e., go to crackberry.com and access it via the Newbies pulldown menu. Lecture 18, How to Download and Install Ringtone on Your Blackberry should provide the details of how to use the desktop Manager or e-mail a ringtone to your phone and load it as a ringtone on your phone.