When I go to the wireless cafe, I can receive and but not send mail using an email client (thunderbird, in this case). I guess this is because I am using pop.myisp.com for the outgoing mail server, but pop.myisp.com won't authorize mail when its coming thru the cafe wireless. Correct?

Is there a way around this? (aside from webmail)
What commands could i use to poke around to find the name of an outgoing mail server?

That's normal behaviour for many places. Your ISP doesn't want connections to its SMTP server from just any IP address because they could be used to send spam. You could check with your ISP to see if they support some sort of authentication so that you could still use their SMTP server.

I don't have any tools to search for open mail relays.

I'd recommend either; using webmail to your ISP, checking with your ISP about authentication; or checking with the wireless cafe owners to see if they provide an SMTP server.

Sorry it's not more help...