You can Connect Multiple Computers Together by Create HotSpot . You can shearing data and internet between them without any Ethernet cable. Only you required Wi-FI enable laptop or external Wi-Fi device. I write process of creating hot spot for windows 7 and windows Xp.
Connect Multiple Computers Together by Create HotSpot

you can create hotspot by following simple 8 step.
process for creating hotspot in window 7

(1) click to start menu