Hi cave12man, I don't know about the website linked to above (and my company's websense filters it), but I'm using an iPhone on T-Mobile myself.
I used an application called ZiPhone. You can find it at ziphone.org. You just hook your iPhone up to a computer and run ZiPhone and follow the steps to activate/unlock/jailbreak. Really easy, had it up and running on T-Mobile within ten minutes after opening the box.
One other thing. If you have the Blackberry Data Plan, you'll need to, on the iPhone, go to Settings -> General -> Network and add wap.voicestream.com under the APN field. If you have the T-Mobile Total Internet Plan for smartphones, you'll want to add internet2.voicestream.com as the APN.
Both plans are the same price, but I'd recommend the Total Internet Plan as it also gives you free access to all T-Mobile access points, including the ones at Starbucks and airports.
I'm using 1.1.3. Haven't upgraded to 1.1.4 yet, but a new iPhone will probably come with 1.1.4. Regardless, I can just do a Restore in iTunes and then update with no trouble, then run the latest version of iPhone to re-unlock it.