Install a new PRL on AOSP based ROMs, CM10, my MIUIv4 by CMBaughman, etc...

InstallPRLOnAOSP

Without CDMA Workshop or QPST:
http://androidforums.com/boost-mobile-warp-all-things-root/532142-guide-how-change-your-msl-prl-not-cdma-workshop.html#post4232529

Using QPST:
(Change Sprint Banner in Firmware how to, including QPST set up)
1. Install HTC Sync if you haven't already.
2. Use the CDMA Method posted Here to get your MSL. Thanks techwerkz - Or Call Sprint. Another alternative would be to gain temp root and use MSL Reader from the market.
3. Download QPST:
http://www.x-drivers.com/catalog/flash/mobile_phones/companies/qualcomm/models/qpst/12051/download.html
4. Install QPST software
5. Put phone into Diag mode: dial ##diag#
6. Start QPST service programming. If your phone is in diag mode you will see it listed here.
7. Click Read from phone
8. Enter your SPC number (the one obtained from step number 2)
9. Click the Display tab.
10. Change the banner to what you want.
11. Write to phone. (You may see some Read Only Errors. This is normal)
12. Reboot phone and you will see the new banner.

Should you encounter issues like the phone not showing up in QPST then more then likely the modem drivers are using a port that QPST does not have as default and you will need to add the port to QPST Configuration. When adding the port to QPST make sure you un-check "Show Serial and USB/QA Diagnostic ports only" or this will not work.

To find the COM port your HTC Modem is using:
Go into the control panel and then device manager. Look for the HTC Modem. Right click on the modem and select properties. Select the "Advanced Tab" then "Advanced Port Settings" Button. Com port will be listed there. (Windows 7 Instructions)

NOW TO CHANGE AOSP PRL ON HTC EVO 3D, HTC EVO V, and HTC EVO 4G LTE (CDMA)

A single file needed changed. 

/sys/class/android_usb/f_diag/on 

all I did was use Root Explorer and edited that file, changed to 0 to a 1, saved it and plugged my phone into my computer. QPST found my phone and I was able to continue the steps to flashing a PRL.

The phone did not reboot on its own, but after I rebooted manually, the PRL was what I flashed!

If you want to use Terminal emulator:

su
echo 1 > /sys/class/android_usb/f_diag/on

Again, I'll do a full guide once I wake up. Didn't want to leave anyone hanging though.