Hey. Mine has been doing the same thing. The first phone I had was resetting every hour or so. My current one is doing it about once a day (occasionally more).
Like yours, it resets and hangs at the pink tmobile screen.
I have swapped everything, including the SIM card and the memory card. I have also done the factory reset, reformatted the SD card, etc. I have also tried to find a correlation between the crashes and the apps I am running, but no luck.
I agree that the problem may be related to the OTA update. Bottom line is I am getting my THIRD phone in the mail sometime this week. After calling the cust. support number they told me that this was 'not a known issue' and when I suggested that they make it one, they said they could not do that...
If anyone else has this problem, please let me know what you have done about it!