How to make an iphone 4 work on T mobile?

I plan on purchasing an unlocked iPhone 4 to use with T Mobile. What is the exact plan I'd need to have in order for the phone to work perfectly? Also, does the phone also need to be jailbroken?

It will work perfectly on any plan, as long as you have a micro SIM(3FF) if you don't have one, you need to ask in a store and they will give you one.

You don't need a specific plan, just one that gives you what you need, I recommend a lot of Internet though, they're very data hungry!

If the phone is unlocked like you say, then you do not need to jailbreak it, just pop in the SIM, boot up, and away you go!

T-Mobile only supports older 2G networks, so that iPhone 4 (you didn't say who it was from) must support that frequency. Here's an article that explains why it doesn't work and why some do work:

http://news.cnet.com/...ver-to-us/

The best thing to do is to bring it to a T-mobile store, they are very happy to help you sign up with them and will figure out really fast if it is compatible with T-mobile.

The second answer above is wrong. T-Mobile doesn't just support "older 2G" networks. T-Mobile has 3G and 4G (via HSPA+ protocols) service.

The problem is not their network, it's with the iPhone. The GSM iPhone from AT&T is designed to work with AT&T's 3G/4G network. That network uses different radio frequencies from T-Mobile's.So, although you can have the iPhone unlocked, and you can make calls and send/receive texts on T-Mobile's network, YOU WILL NOT GET HIGH SPEED DATA. You will get 2G/EDGE data speeds because the frequencies for T-Mobile's 3G/4G won't work in the iPhone.

If the iPhone is unlocked, it shouldn't need to be jailbroken. However, you will have the restrictions above, which really makes this pointless. Why would you spend all that money on an iPhone and not be able to get fast data connections?