Steve, a couple of years ago SBC was asserting that they held the rights to the use of frames and were hounding folks about it. There were a few articles on slashdot about it. Museum Tours had a letter they received on their web site but it has been removed.
slashdot org/articles/03/04/30/2116207.shtml?tid=
I had a couple of site using frames but I converted them to avoid problems.
Jim