Send/Rec files via modem..

Ok, here is my situation. I need to send/rec files to different outside sources.
A developer working on this couldn't find a unix program to dial out so he is
going to go with a 3rd party software on a NT box. eww

So, this is what I'm looking for. I would have a modem on a sun/linux/hp box and
it would send files out via a modem to another modem. It would also go and
pickup files on these external boxes as well.

Does anyone know where I can find information on doing this? Also, if you know
of a software program for unix, please share.

Thanks in advance.
Eric
:: email removed ::

The first that comes to mind is Kermit .

I haven't used it in years but it was a great utility years ago and from what I saw on the web page (case studies) it looks even better than ever.