Start - Settings - Connections tab - "manage existing connections" - then edit bradband acc. When in that area, just delete the password. The password is ALWAYS vzw so if you want to use data, it will ask for the password and then you just type it in. This way, you will always know whether or not your connected to data services.
if you want to completely get rid of data services (cellular, not wifi) is just delete the broadband access connection. Beware though because if you update your prl (*228 option 1 or 2, or even *22899) then it will put that setting back in there. Just be sure to go back and delete it again!
[exploring a verizon phone without data plan; other is that voice is 800 hz and data 1200]
You can prevent your device from using the Verzion Broadband connection by going into Connection Manager and change the Network Management (Advanced tab, Select Networks) to use "My Work Network" instead of "My ISP" for both the Internet and private network. Your connections will now only use WiFi.
... hmmm ...