Anyway, I came across this screwing around a couple months ago when I wanted to reset my PRI, and apparently it still works with 2.1 roms.
Before doing this make sure you have aLogcat. Also its easier to find your MSL if you go into logcat and "clear log" before doing these steps.
**Refer to the attached pictures if you get lost**
- So step 1 is to go to your dialer and enter ##DATA# or ##3282# which will bring up the EPST menu
- Once the menu pops up just select "View Mode"
- At this point you will see a screen with 3 selections.
- From here either press and hold the Home Key and select aLogcat if you ran it before, go to your tray and run Logcat.
- After opening Logcat it will update, once it finishes press "Menu" and "Pause" the log.
- Then scroll until you see a group of entries labeled "I/EpstBroadcastReciever" which should be green
- Locate the line that has "MSL Code=" at the end of it
- Edit: Or press Menu and Filter "MSL" (thanks wjason)
Please let me know if this actually works for you guys as I have only been able to test it on 3 phones so far.