If they pull a hard inquiry on you when you apply (which they usually do), the presence of the inq can hurt your scores, depending on how many inqs you already have. Generally, the higher the scores, the bigger the hit.
This is true of all wireless services that I'm aware of. Otherwise, they don't report at all on your credit reports, unless and until you get behind on your bills and get sent to collections. Then they'll
really hurt your scores.
* Credit is a wonderful servant, but a terrible master. * Who's the boss --you or your credit?
FICO's: EQ 781 - TU 793 - EX 779 (from PSECU) - Done credit hunting; having fun with credit gardening. - EQ 590 on 5/14/2007