Data plans are not shared between devices. So with having a data plan on your iPhone, it would not be shared with an iPad2. However, we have several data packages to select from to go with your iPad2. I am providing a link for the Data plans and you can always switch from using your Wifi to the Data plan with it being on your iPad. For example, you could be at a place where Wifi is available, and change over to that connect to use the Wifi. Then when you go out somewhere the Wifi is not available, depending on the area your in at that time, you could use the Data plan to use your network as your connection to the internet.
Here is a link to the Data plans available: http://www.verizonwireless.com/b2c/mobilebroadband/?page=plans