BT works just fine with linux (Once you have bought yourself a proper DSL modem with an ethernet connection, their USB thingy is &^%!)
Try this:
Start kmail.
Settings-Configure kmail
Identities: Enter your name and email address.
Network-Sending tab. Add. General Tab: Name=BTMail, Host= mail.btinternet.com, Port=25, Server requires Authentication=Put an X in the box, login = leonardo38 if your address is
leonardo38@btinternet.com, Password=Yourpassword, Put an X in the box labelled "Store SMTP password in config file". Now click the Security Tab. Set encryption to None, Set authentication method to Plain. OK for this bit.
Now we are back at Sending Tab, which we have just set up.
Click the Receiving Tab. Add. Now set it up like this:
Under the General Tab: Name= BT Mail, Login = leonardo38, Password= Yourpassword, Host= mail.btinternet.com, Port = 110, [X]Store password in config file, [X] Enable interval mail checking.
Under the Extras Tab: Encryption: None, Authentication method = Plain text
Click OK.
Enable "Check mail on startup" Click OK.
You should be done.
Restart Kmail, or do File-Check mail, it should work.
Hope this helps,