1. Using P2K Commander or P2k Tools, download the "plmn_text_table.bin" file [2] (in a/ directory [1]) from your phone to your computer.

2. Open the file with "OpEdit"

3. Click on the top bar labeled "OPERATOR NAME" to sort the list in alphabetical order. [3]

4. Scan through the list until you see your carrier's name (i.e. Cingular/T-Mobile) [4]

5. When you see your carrier's name, click on it (three times) to rename it. Rename it to whatever you like.

6. Repeat step 5 for every time you see your carrier's name.

7. Save the plmn_text_table.bin file, and upload it back to your phone.

8. Restart your phone. [5]

Pictures attached. They dont really have to be arranged in any particular order. Use them for reference with bracket numbers.
Walkthrough by art2d2tx. illustrated by duccodude