According to different sources, the T-Mobile MDA (equal to the O2 xda but with a little bit different design) is ready to be released soon at least in Germany. Today no word was given about an introduction in the US American VoiceStream network. Also the European MDA differentiates from the American as the European one will be launched as dual-band supporting GSM 900/1800 MHz while the US MDA will support 900/1900 MHz.
UPDATE: According to the latest information, the MDA should be launched on 15.07. - which is next Monday! Still no word about other T-Mobile subsidiaries like Austria, USA or UK. Seems as Germany becomes the #1 PPC Phone Edition country... ;-)
As far as I've heard also, T-Mobile is planning to introduce - right with the launch of the German MDA - a Pocket PC optimized Web portal. This should includes at least all T-Mobile WAP categories like: