Port Blocked.. need forwarding/relay server setup.. i think

hey group,

I've been trying to circumvent a problem that i'm having at work sending mail through an smtp server i have that is a virtually shared setup through a large webhost.

I know the server works because i can use it at home but at work they have port 25 blocked apparently.

I'd like to setup my smtp server at home to listen on a port other that 25 and send mail for me.. even if it relays it to our shared mail server..(which is probably desireable)

my problem is that there are so many settings I'm not sure where to start and i'm also not very familiar with what all the terminology means.

could someone please help enlighten me as to what I'm REALLY trying to do and what parts of the smtp server(sendmail currently) i need to change.

Many Thanks!
Will