Interconnect wired and wireless using laptop?

Hi,
I need to network two laptops and a desktop.. The two laptops are easily connected using wireless lan.. Now by connecting one of them to the desktop by an ethernet cable, can i set up a network involving all three computers? I tried age of empires lan game between the three and everything goes fine until the final step where it fails... Moreover can i share files between the three thus connected? Will a special protocol like IPX help..? I'm a newbie to networking and somebody kindly explain how to connect the three using the above said method, if at all they can be?