[Vlip3]

I have a similar question to the one posed by Eph445 recently. I've read all the stickys and most of the posts in this and other threads but nothing seems to address the issue of carrier specific customization of the phone. I have an Alltel Touch Pro. What will I need to do to get my phone on the Alltel network? Does this happen automatically over the air? How does the phone know what its phone number is? For example, when I do a hard reset, it goes through a lengthy customization in which the messages displayed have file names that include "alltel".
I've done a number of customizations of my phone (mostly using Diamond TF3D config & Advanced config) but flashing the ROM seems to be at a whole nother level.

Thanks in advance for your help!