i've been having trouble being able to set up my thunderbird and entourage email clients...i can recieve emails perfectly fine but i cannot reply. my boyfriend said it's something to do with my ISP, which is sbc...and they don't allow you to send emails through clients like these.

any suggestions or ideas on how i can get this working?

You need to use the SMTP settings from your ISP.
In Tbird click on Tools/Account Settings, then the last entry on the left that says Outgoing Server (SMTP).
Under Server Name, put in the SBC-server entry on port 25.
You MAY also need to put your userID/Password in there.
SBC has nothing to say WHICH email client you use!

If you have started or migrated to Yahoo then your email settings will be:
Incoming Mail Server: pop.sbcglobal.yahoo.com
Outgoing Mail Server: smtp.sbcglobal.yahoo.com

If your email is @sbcglobal.net then:
Incoming Mail Server: pop.sbcglobal.net
Outgoing Mail Server: smtpauth.sbcglobal.net
For details see: http://global.swbell.net/help/sims/