said by Mynameismine :
Just purchase a At&t Datacard from Ebay..Go to At&t.com, login into your account and change the ESN number..Your plan should remain the same
Probably not in desertJim's case, they are actually going to migrate him from EVDO to a GSM based technology. They cannot migrate him into their billing system without a completely different modem.
One he is migrated, he can switch modems at whim by just changing the SIM into a new device, no ESN change needed, but then it will be too late.
Don't feel too bad though Jim, it appears that Alltel is invoking the 5GB cap even on customers that are not migrating :-(
HTH