Sprint 4S unlock

Are you looking to use it on another network? Because I've been researching this for a few months. I have a sprint 4s and I have yet to find a reliable way to use it on another network, i.e. tmobile. There are a few SIM cards (Gevey, Rim-7) but looking at the reviews they don't seem to work reliably. When my contract is up I'm probably just going to sell the sprint 4s and get an unlocked AT&T model so I can use it on tmobile or wait for the tmobile iphone.

just bought the "New GPP" sim card for my Sprint iPhone 4S and can confirm it does work with ios 6.1.1 with my att/straight talk GSM 4G HSPA service... although (like all interposer sims) it takes some patience and experience with carrier preference settings to get everything working perfectly. although it does work... i cant for the life of me figure out why i cannot PLACE outgoing FaceTime calls. I can recieve them just fine. when i EJECT the sim i can make outgoing FaceTime calls instantly. weird huh?

That's good news. I'll have to research the GPP sim. Does FaceTime work over wifi both directions?

I also have the GPP Sim and it works perfectly . If you want I can tel you where mine was purchased . I didn't test Facetime so I wouldn't know if it works sorry.

I went to AT&T and tried to swap my services from sprint. My 4s that I have with spring could not be done because AT&T SIM card will not would not work on my sprint. So to make a long story short I'm still with sprint.