Can someone help me setup a wireless network with a linksys wrt160n router, 24" imac, and comcast modem?

i use wireless connection for playstation network, however lately it hasn't been connecting at all and i need my call of duty fix!|||you have to actually call your internet provider or have someone at your house that knows a lot about computers. It is a huge process to get one set up. It took me an hour over the phone with comcast. it does work now though.