Disclaimer: I'm not responsible for what you do to your phone while preforming these steps, the info here is not made by me but is a mix of previous experience and a few other guides on the internet.
as of today (9/28/2010) DATA and SMS (Picture messages) DO NOT Work, I'm still trying to figure that part out.. However Calls and Text and all the other functions of the phone do work!
1st) thing you have to have is root for your phone, if you have that then great! Also you need to be running a NON-Froyo Rom (the froyo roms, I've tested thus far) are lacking EPST which will be used later to program the phone.
2nd) Search the Market (Via WiFi) and download MSL reader
3) Write down that MSL (will need it later)
4) reboot phone
5) download
http://www.bpcr.biz/buddy/Android.zip and put on root of SD card
6) on your phone pull up the dialer (hit the green button) and put in ##775# (##PRL#) and put in your MSL code you got earlier
7) select "update PRL", drop down "Folder" to "SD Card" and push down on your navigation ball and then long press the "menu" key to make your keyboard lower and select pageplus.prl then select "ok", then press your "menu" key and hit commit modification
8) phone will reboot (Congratulations your now on verizon towers!
9) Get PagePlus to activate phone (eg, contact a local dealer) , tell them you are manually programming a Sprint phone and give them the IMEI and that you need your MIN/MDN and SID.
**Update**
Easier method!
10) on your phone, pull up the dialer and dial ##YOUR6DIGITALMSL# , then select edit mode
11) change Mobile Directory Number (MDN) to what is given to you by PP/dealer
12) change MSID to your MIN (Mobile Identification Number) as suplied by PP/Dealer
12) press menu
13) commit changes
**** older method***
10) Now that you have that information, dial ##3424# on your phone
11) Click "edit mode"
12) Enter the MSL from earlier
13) Select Data Profile, then change the username to
YOURPHONENUMER@vzw3g.com
14) press your physical menu button and select commit changes
15) re-do steps 10 and 11 but this time, select Advanced instead of data profile
16) now select MSID and change it to your MDN
17) now select Home SID/NID, input SID supplied by PagePlus Dealer and NID is ALWAYS 65335
18) press your menu button again and commit changes
19) ENJOY your pre-paid HTC Hero!
************* UPDATE*******************
I now have working data with PagePlus, now to solve MMS problem!
Will update shortly with tutorial on howto get data & MMS