Helpful Ham Radio Links from the Rocky Mountain Radio League
Digital:
MD-380 Tweak (very popular)
Brandmeister Getting Started Guide (from PAPA, a southern California repeater system)
Other:
Denver Area Ham Radio Net List
Colorado Council of Amateur Radio Clubs
Federal Communications Commission
The Internet Radio Linking Project
IRLP and Echolink World Net List
The Radio Amateur Satellite Corporation
World Time Buddy (times around the world)