http://hraunfoss.fcc.gov/edocs_public/attachmatch/FCC-04-223A1.doc The FCC has extended another delay (from Jan 1, 2005 to June 30, 2005) on its requirements that you must have written permission from your customers before you fax. Until June 30th (or Congressional relief), an existing business relationship can be used as express permission to fax.
The link is to FCC's website; CG Docket No. 02-278; Order adopted 9/15/04, released 10/1/04