I received the MB6000 on the 20th Feb 2008 and the firmware that came with the device was v1.1.18 which did not recognise my T-Mobile data card.
The latest firmware v1.1.28 is on Top Global's website at the following address, and this recognised the data card straight away:
http://www.topglobalusa.com/support_mb6000.htm
The last thing to change is to go into "Internet Access" on the device and change the default data connection settings from Cingular to your network's settings.
Apart from that I'm very impressed with the device and its specifications. The only slightly annoying thing is that it's a bit big to carry around in a computer bag, so more suited for a fixed location.
Good product... More