I'm checking up on use of the iPhone on T-Mobile here in the US and the usual carriers in europe .. i.e. unlocking the phone and using it on carriers other than ATT.

What has it been like to unlock and use your iPhone?

Specifically:

1 - Is there a certain way to make sure you can unlock your iPhone as new Apple upgrades occur? As I understand it, the unlocks always use bugs in the the iPhone software. Is there an unlock solution that looks stable over the upcoming versions of the iPhone firmware?

2 - Does the unlock really let you not only use the iPhone on T-Mobile in the US but also in europe with the pay-as-you-go SIMs popular with us GSM travelers?

3 - What has been the experience of T-Mobile users here in the US? I'm a T-Mobile user and ATT doesn't work where I live, but T-Mobile is fine, and I like the T-Mobile HotSpot plan.

Thanks!

-- Owen