B-dub -

Illegal has nothing to do with it. The criterion is "can they get by with it."

I also had the impression that the original no-call law prohibited calls to cell phones. That was given as the justification for not permitting the listing of cell phones. The Fact sheet I linked above indicates that you can now register "wireless" phones, so perhaps the rules have changed.

The original regulation governing the US Do Not Call list may be seen at:
FCC 03-153A1 or at numerous other sites.

("FCC 03" in google will get many sites, nearly all offering .pdf versions. This one may not be the most "official," but they all seem to offer the same document - 160+ pages of it as I recall.)

I haven't found a site that offers amendments and changes to the law. Most likely some of the changes are by FCC rules rather than by legislation.

John