roni--hmmm...sounds like you had a port issue of some sort. My desktop Mac (the one acting as the base station) is the only one that I check my email on (at least via an actual email application; I sometimes check my mail on the iBook via the web, but that uses standard web protocols).
It might have also had something to do with the Advanced UDP/Stealth Mode settings under Tiger--I found that if I had "Block UDP Traffic" checked off, I was unable to access the iTMS or any streaming audio/video clips, so I unchecked it.
In any event, it works very nicely for our purposes--and it's one less power cord to clutter things up :)