I got this working on my EVO, and I am using a custom domain email that uses Hotmail, so should work for everyone. However, I had many failed attempts with the HTC app, I decided to install the stock android email app and it worked. I have attached it, I just extracted it from the CM6 rom which does not use sense. Works great, all i did was put it on my sd card and installed with astro, did not have to push with adb to the sys folder or anything. And it is running side by side with the htc app, which i still use for my yahoo accounts. Not sure if you have to be rooted, but make sure you checked unknown sources in the applications settings.
Here are the settings:
On Froyo 2.2:
Username:
username@hotmail.com (or @live.com)
Password: **********
Domain\Username: \username@hotmail.com (or @live.com) make sure you include the "\"
Server: m.hotmail.com
Make sure you check both "Use secure connection (SSL)" and "Accept all SSL certificates"
I think the problem with the HTC app is that it does not have an option to accept SSL certificates, so it is either doing this auto or does not support it, i am guessing it does not support it and that is why the final setup is failing.