Anyone using an external modem?

[Black Landlord]

Aaaargh . . . I just came to the realization that my new iMac has no modem; I have a fax program that I use constantly to send out press releases and other things, with scores of numbers built in.
Can anyone recommend a USB modem that plays nice with an Intel mac? Is there such a thing?
[groan-- can't switch to new mac until this is solved . . .]