I'm looking to begin iPhone development and I'm curious how registration of "developer" phones works. I have a 3G for daily use but I still have my original iPhone sitting in a box. Will I be able to register and test apps on my old phone even though it no longer has cell service? Also, down the road would I be able to register my 3G to test GPS functionality (i.e., have both registered to my account)? Thanks in advance.