The unlocking is done completely on the Storm handset itself, no need for a pc (or Mac). To get the code you either ask Verizon for it (free, but you need an account in good standing with them, minimum 90 days) or buy it from someone like
Horizon Wireless. I highly suggest using a reputable service like Horizon Wireless. So many of those bargain-basement services are either scams or just plain incompetent. Horizon is a class outfit with tons of positive feedback by forum members here.
How to Enter Unlock Codes on BlackBerry Storm 9530 9500:
1. Insert any sim card
2. Turn off all of the wireless connections
3. Go to Options
4. Select Advanced Options
5. Select SIM Card
6. Hit menu select show keyboard
7. Enter mepd (you will not be able to see the typed info)
8. Enter mep2
9. Now it will say enter network mep code
source: Phone Liberty » How to enter my Unlock Code on Blackberry?