Hi mefnj,
You make the following two statements, but the second one isn't quite a clear as the first one...
1. what i am trying to do is allow my iPad to use my phone's 3G internet connection and my paid data plan
2. i am trying to use my iPad INSTEAD of my phone for internet access, so i am not "double dipping" my data usage
I am going to assume you want your iPad to use your phones 3G connection for internet access, so you can make the most of your phone data plan.
In this case you MUST have a tethering capability on your phone in order to be able to do this. You cannot magically enable something on the iPad which will allow you to tether from your phone when your phone does not have any tethering capabilities enabled
AFAIK (unless the HTC Incredible does something I am unaware of).
iBluever may allow an iPad to connect to a phone over bluetooth, but it does not enable the tethering on the phone itself. All that will happen, if you do manage to get iBluever working, is you will get connected to your phone via bluetooth, but you will still have no internet capability on the iPad.
So iBluever is intended to allow you to use your phones tethering ability over Bluetooth, but it does not enable it.
Personally, I think what you should be doing is looking at rooting and enabling wifi tethering on your phone as laid out in the last reply. Then no modifications are necessary on the iPad (or any other wifi enabled device).
In this scenario you enable the tethering on your phone without paying the extra tethering fee to the carrier.
If this is not correct, please try to better state what it is you are trying to achieve with each device
Good luck.