Any ideas on how to convert a USB wired connection to a WiFi Connection?

I want to build a sentry gun(link below) for when my friends and I airsoft. The only problem, it requires a wired USB connection to an Arduino. It would be AMAZING if ANYONE had ANY ideas to make it wireless. I don't think I'm the only one who thinks this would be an advantage.

I know you guys will probably tell me to use a WiFI modem. My only problem with that, I DON'T KNOW HOW TO DO THAT! So that would help to.

Much Obliged

(http://projectsentrygun.com/)

Can't see the link here at work, the site is blocked. But if this gun is using an Arduino to control the motors and needs a connection to a PC to receive commands then you need to add an Arduino xBee shield. If you don't know how to add that then go the the link provided and learn. You can find plenty of help for integrating the wireless solution at the Arduino Forums.