email sending problems debian 4.0

[lists at barrettpianos.co.uk]

All,

Would appreciate some advice as I am having problems sending e-
mail with debian 4.0.

The current position is that I can collect mail from my isp and read 
it with mutt.  I am using fetchmail to collect from the isp.

I need to use the smtp server at the isp to send mail 
(relay.plus.net).

I have googled but most of what I can find appears a bit daunting 
for an absolute beginner.

My questions are, would exim or sendmail be the better choice?  
Am I right in assuming that exim would be used to receive mail as 
well.  Would sendmail be more simple?

Would appreciate it if someone could point me to some 
documentation to explain all this?

Thanks

Keith