speedometer recalibration

So I put 3.73 gears in 2002 T/A, used to have 3.42's. Where can I go to get the speedo recalibrated? Thought just an OBII scanner could do it, but my buddy that has one says no, he told me to just buy a hypertech programer but those are like $400. Can a dealership make these mods to the computer? I just got done rebuilding the 6 speed & the rear end, cash is getting a little on the low side lately so im looking for a cheaper alternative. Would a speed shop be able to do this?

Thanks

I wouldn't go to the dealership. They might reset to factory specs. I'm sure a speed shop could program it, either with a plug in or flash it with the dyno computer.

That's a good question, I need this done too, cheaply!

This is who I use to dyno tune my car http://www.pcmforless.com/ . His name is Bryan and he is very well known for his skill as a tuner as you can probably see, he must be good to do Mario's car. He is cheaper for OBD1 hybrids but if you are going to pay for a reprogram you may as well get a performance tweak tune as well. The local shops may be a tad cheaper.

Edit- Just as a source of the reference the following members also use him. Cuda_dude, Drvngstorm05 , Genopsyde91 and myself.