It can if you select the option to do that. Once you start the wipe, a popup will appear asking if you want to do that.
On the negative side, I have read that this doesn't clear EVERYTHING. It has worked for me in the past, but if you're worried about someone nabbing your personal info, try BBSAK (or whatever it is). It's an application for your computer that should completely wipe the device. But again, the bad side of that is completely means completely and you will have to reload the OS and anything else you (or the buyer) wants on there.
Good luck!
Posted from my CrackBerry at wapforums.crackberry.com
