If you're switching to another Blackberry, then you can make a backup file and then restore it on the new Blackberry. Unfortunately if you need them on the SIM card, I've only been able to do one contact at a time. You open the contact that you want to transfer, click the thumbwheel, and select copy to SIM. Some people have talked about a way to do it by making a text file, I'm not sure how that works.
T-Mobile Bold 9780