The handset went through the FCC and the Sony Ericsson TM506 is available at T-Mobile. The handset comes for about 80 USD with a contract agreement, probably two years.
The TM506 is available in the US since September 5 so you can go and purchase is with no real problems. The handset has HSDPA support in T-Mobile’s 3G network. Additionally it comes with a 2 megapixel camera, built-in media player with stereo Bluetooth and TeleNav navigation.
It seems that the Sony Ericsson TM506 comes at a price judging by its features. The handset is pretty reliable as all SE mobile phones are.