Can you still use iPhone without service?

[groggy23]

I actually have 2 questions. First, can you still use the other iPhone features without subscribing to the AT&T service, such as Wi-Fi, iPod, etc..? Thing is I have T-mobile, and I know they have unlocked software available I think. Which brings me to my second question. Will using this unlocked software void warranty?

[deftdrummer1]

1) yes you can use the iphone as a wifi ipod if you unlock it.
2) yes it voids the warranty if you use this software. I think a restore might make it look like it never happened though.