These are some links to other sites that we like or find useful. Enjoy!
MSD2D - Exchange Server Developer's resource
Slipstick - Good resource for Exchange Server solutions
Joel on Software - Very good thoughs on software development
RFC821 SMTP - How mail gets transfered to the Exchange Server
RFC822 Message Format - General format of internet Emails
RFC1939 POP3 - The POP3 protocol
RFC3501 IMAP - Internet Message Access Protocol
Kiva - loans that change lives - Off topic but we believe Kiva is a really good idea and we support it every month.
More of our own sites: