As far as advice its based on your taste. The basics as far as ROM upgrading or even unlocking are recommended, check out these 2 threads
http://forum.ppcgeeks.com/showthread.php?t=17473 this 1st one is flashing 101...
http://forum.ppcgeeks.com/showthread.php?t=20370 this one is you unlocker and its also covered in flashing 101...LOL!!!
Basics like installing .cab files are also necessary for those looking to mod their phone, activesync or WMDC "Windos Mobile Device Center" are all important for you to learn about...Just remember to use a back-up utility for all your contacts and anything else. Oh yeah and thanks for joining the family...
Enter I just found this
http://wiki.modaco.com/index.php/Get...Windows_Mobile
It is possibly the most useful thing I have ever saw.