Search for GetSPC and the instructions to get the MSL for the Sprint phone. Go to this site and download the Alltel PRL
http://corolada.com/prl/. Copy the PRL file to the phones memory. Dial ##778 and use the MSL that you got to enter the NAM programming on the phone. Go to the PRL page and choose update PRL, browse to where you saved the file and select it. Now you can activate the phone with Alltel and try to program it over the air by dialing *228 option 3. If it will not program OTA you will need to dial ##778 again, enter the MSL and select edit again. You will need to enter your SID, MIN, and MIP settings manually. You can find the SID for Alltel in your area on the Coroloda page also.
Thats the gist of how to do it, You can search for my previous post where I gave a few people detailed instructions on how to do this with their 6700's.