The two internal modems listed on:
http://www.mwave.com/mwave/doSearch.hmx?bop=and&scriteria=Linux+modem&UID=&CID=&Back=&n=1

are:
http://www.mwave.com/mwave/doc2/250881.html
http://www.mwave.com/mwave/doc/a10740.html

It's just for personal use, not even heavy use, as I have broadband.  
But I do want to have the ability to fax, possibly set up a faxing 
system in the future, not be perturbed by call waiting, and other nice 
hacks, like maybe my own voicemail system or paging or the like.  If you 
know of any clever software for things like this, let me know as well.

thanks,
--Alexander