[Mailman-Users] Bulk Emailing

[Dr Mikel]

Hello All,

I have look around and can't seem to find the answers.
I new to the mailing list scene and need some help, I have setup mailman and 
it seems to work but i can't post emails.
e.g.

new list - nl1
subs     - me at here.com,test at me.com,hello at there.com

when test at here.com sends an email to nl1 at test.com nothing happens, i dont 
think sendmail is doing anything.
Whats going on?