Using a Air Card on Verizon is possible and thats how I actually get my PS3 online. It is a bit tricky though since there both USB inputs you have to have the air card installed and connected. Then go to newegg and buy this thrustmaster Wifi key.
Install the driver software and open the connection up. Your PS3 will pick up the connection. You can do Wep encryption if you like. I don't bother since my closest neighbor is a quarter mile away.
The only downside is you'll need to have your computer running and connected to get online with the PS3. Also they currently do not have a Vista driver so I have to boot into XP to use it. Thrustmaster is working on a Vista driver but to my knowledge its still not out. So if you have Vista only this isn't currently a option and you'll have to use the below option.
If you didn't want to have your computer running to get online with the PS3 there is one other option.
You can get a Wireless router for the air card. I use a 595U what type of air card are you using since each card supports different wireless routers. This is a good one if your using the 595u.
I moved my thrustmaster key to the front and took a pic of it and the air card. Its about 6 inches long and the wire is bendable. Normally I put it on a back USB slot so its hidden but I moved it to the front for the picture.