I have been using cooked Windows Mobile 6.5.1 ROMs for a while now on my Touch Pro.
Recently I installed the latest build from Microsoft: 23502 which is part of their COM5 development branch and it is a great release!
If you have a custom Windows Mobile 6.5 ROM you might be running into issues connecting to the new Windows Mobile Marketplace.
Here is a very simple fix I found out while looking at different forums.
Did you know that you can watch live TV for free on your iPhones?
It's time to use the most of your 3G connection and enjoy TV in the palm of your hand!