All SO phones are already "pre-activated" with phone numbers. You must provide SO customer service with the account number and phone identifier to prove that you own that phone number before you can port it to the SO phone.

SO does not charge for porting a number in, although you may get hit with charges by your other cell phone provider.

The balance in your SO phone account will remain intact when the number is ported in. You cannot transfer the remaining balance from your other account to the SO phone.

I ported my number from a Telus pay as you go phone to my SO phone. It was really easy, and the hardest part was pulling the battery off the Telus phone to read the phone identifier (not difficult).