http://www.clearwire.com/support/help/pages/emailweb_outlook_exp.htm
The setup appears to be exceptionally easy to follow.
Are you trying to set up just the default clearwire account? do you know if you have or want to have imap or pop3 type email access?
Understand that the incoming and the outgoing can be tested separately by sending to a gmail or other web based account.
If you really get stuck after dealing with the tech support, email me or post here and I will be able to fix it or determine what is wrong.
For those playing along at home…
http://www.village-elder.com/blog/archives/1-How-to-test-a-mail-server-by-sending-mail-with-telnet.html
I keep my own scripts to test email servers via telnet but this one is well commented and fits recent versions of mail software.