Got a T-Mobile Dash or some other new-fangled Windows Mobile smartphone that has the latest update, aka: AKU3? If so, then say bye-bye to the Bluetooth Dial Up Networking (BT DUN) profile. Based on this post over at Pocket PC Thoughts, BT DUN is now resting peacefully with its distant relative known as "WiFi Synching".
It’s not all bad news as the BT DUN profile was essentially replaced with the BT PAN, or Personal Area Network functionality. This will likely still work if you use your Windows Mobile device as a modem for a laptop or UMPC, but be prepared: you’ll need to do some Internet Sharing, perform some extra clicks and spin your chair around counter-clockwise three times just for good measure. All of the details are in the original post and if you plan to get a new device with AKU3 and you use your handheld as a modem, you must read this for all of the details.