I am about to sell my BB and there is an option on it to factory reset (or something like that), will this wipe all personal data from the phone?
Thanks

yes it will wipe everything except your sim card.

Yes it's in the Security option, just make sure that you tick to delete data and personal info as well, it asks you to type the word blackberry as confirmation.

Takes about 10-15 mins to complete, make sure your battery is charged up and don't pull the battery out part way through :-)