I downloaded the trial version of CS Fax a couple days ago and was very impressed. You can even download over the air directly to the Treo, which was helpful for me since I'm away from home and I'm having sync issues with my laptop. Anyway, it was easy to install and I was able to receive a fax, sign it and send it back with no trouble. You can even make up your own cover pages. They've got a beta out which will allow you to use existing documents (.doc or .tif) for your faxes. The only drawback is the price...$49.95, ouch! Not sure I'd need it enough to justify that. The only reason I'd consider it is that, with my work hours, my Treo is my only phone, so personal faxes or when I'm away from work would be my issue.