There are many descriptions here and in other places on the web about how simple it is to enter a SIM unlock code on a TP2 with the original ROM. However, as is apparent from fruitless searching here and elsewhere, the MR2 update removes the ability to get to the screen needed for the entry of the code. I wasted several hours digging around here and on my TP2 looking for a way to do it.
While I was looking for some utility to allow me to access the screen, or, at least exit HTC Sense so I could get to the Win Mobile controls, I ran across a very nice app at Freeware Pocket PC,
Freeware Pocket PC. Free Software and Game Downloads for Windows Mobile and Windows Phone 7 This site has an app called Link2Cpl. After you install it an run it, it gives you a list of control panel items you can check off. It then inserts into your program list links to the screens you checked off. The direct web link to the program is
Link2Cpl v1.00 freeware for Windows Mobile Phone.
I got the program using the OMarket app that the site makes available for Win Mobile. As MSFT ignore WinMobile and its marketplace, I imaging that the above site will assume more importance.
BTW,when I called Verizon Global Support at 1-800-711-8300, the procedure was a breeze. I didn't know which menu option to choose, so I just hit 1 and explained to the rep what I wanted, he knew about it and looked at my account to make sure I was eligible before transferring me to a Technical rep for the code. Both reps were extremely nice and the whole thing took less than 5 minutes.