It varies by phone, by I'll try to give you the concise version:

1. She'll need a phone that is 1xRTT or EV-DO compatiable. Most VZW phones are 1xRTT at this point. The newer ones also support EV-DO. The difference is that 1xRTT offers speeds up to 115kbs and EV-DO goes up to about 300kbs (in theory).

2. Once she settles on a phone, she'll want to add a data plan on to her service. The cost of the data plan is over and above the calling plan. She'll need to pick one according to her expected usage; per megabyte (cheapest/charged per usage), 10-meg, 20-meg, or unlimited. If she doesn't know what her usage will be, a good starter is the 10-meg plan.

3. After that, she'll most likely need to get a data cable. Verizon sells some but they can also be found all over the internet. This will connect the phone to the computer. If she's lucky, the phone she chooses will come with one.

4. Finally, VZW will provide her with a piece of software that will facilitate the connection to the Internet through the cellphone. Once connected, she can use the Internet just like she was at home, albeit a little slower.

Now, I mentioned the Howard Forums site b/c it's a free and large forum that deals with cell phones and hacking. Some cellphones can be hacked so that instead of using a data cable, you can connect wirelessly using BlueTooth. That would require the phone and computer both having BlueTooth and the phone being capable of being hacked to use it. But steps 1-4 are the most basic and will get her going.

If she's technically inclined, you might want to steer her towards a PDA phone like the Treo 700 or UTStarcom XV6700. Both allow the net to be used on the phone itself (you can surf right from the phone) AND have the ability to be connected to a laptop.