Cell Phone Service provider lookup

I don't think that's possible.  People have been able to port numbers with such ease for so many years now that the number is no longer definitively associated with the carrier.

check out this site.. I'm trying to replicate what they give for a response w/o having to manually enter a bunch of numbers...

http://www.fonefinder.net/

If they allow it, you can probably just do a query out to their site whenever you need programmatically, depending on the volume, but, again, the cell provider isn't going to be accurate in a lot of cases.  Just tried a number I ported in the past, to be sure, and it showed up as Cingular, when it is now on Verizon.

hmmm. I did a test on my number which I ported in the past and it showed as verizon and I had just switched off att 2 months ago. How would I go about getting a response back from the site?

For that site, most places don't like it if you hit them with scripts in bulk at all.  Outside of that, some places will provide APIs you can follow to get the information returned in whatever format you want with a proper query sent to them.

The only places I can find that will let you do what you're asking are all semi-legal, black hat links.  Typically EE disapproves of posting those, IME.  You can find some services and options in Google if you're doing something semi-regular.  Sorry I can't be of more help.  

Found a few solutions.