This works great on my Incredible. No rooting required, but you must have the 2.2 update which enables the 3G Mobile Hotspot on the device.
This supposedly only works on the HTC Incredible.
As the previous posts in this thread explain (step by step):
1. Select "Phone"
2. Dial "##778"
3. Select "Edit Mode" on pop-up dialog box
4. Enter "000000" for Please Enter Password (unless you manually changed your password to something else)
5. Select "Security"
6. Select "S.IP DUN User Name"
7. Delete the "dun." part of the number (ie: it should read as: [yourmobilenumber]@vzw3g.com)
8. Select "OK"
9. Press the "BACK" button
10. Select "M.IP Default Profile"
11. Select "DUN NAI"
12. Delete the ".dun" part of the number (ie: it should read as: [yourmobilenumber]@vzw3g.com)
13. Select "OK"
14. Press the "MENU" button
15. Select "Commit Modifications"
16. The phone will reset
17. Once booted, go into "All Programs", select the "3G Mobile Hotspot", Adjust your "Router Name" and "Password" (if you desire, but recommmended), and change the security to WPA(TKIP) (this is the only setting I've tried so far-other posts said the WPA2 is buggy)
18. Select "3G Mobile Hotspot - Press to turn on" (It will prompt you that you need the Verizon Mobile Hotspot Feature- just hit "Do not remind me again" and "OK") (Also, I am using Windows 7x64, and the wifi picked up the signal right away, but it took a moment to identify-but it connected to the internet cleanly and the connection is fast)
19. Optional: Download "Hotspot Toggle" from the Android Market- it's a widget toggle to turn it on and off- seems to work good.
I checked my Verizon account immediately after using this, and I didn't see that the "3G Mobile Hotspot" feature was added to my plan.
Keep in mind: Verizon may not be checking to see how you're using your Android, but they may check to see how much data you're using through the phone. With how much data that flows through the phone without tethering it to a computer, it would be difficult for Verizon to determine if the data use is coming from the phone or tethering. But mobile hotspot could pull a lot of MB if several people are logged on. Just be cautious. A big spike in data usage could send up a red flag.
NOTE: I did not come up with this theory. I just rewrote it step-by-step due to some confusion I was noticing (hopefully I didn't miss a step).