I have 1 laptop and 1 desktop. I want to share files and other applications. laptop has Vista and desktop too with 1 GB RAM and 120 GB HDD. How can i network them both to share and access files and printers. If I want to wireless network them how will i and what do i need . please help me out.

There are a couple of ways to share files from different computers. But in all cases you must have sharing enabled

Windows Vista Help: Enable file and printer sharing

This is an article discribing the type of hardware that needs to be used:

Windows Vista Help: What you need to set up a home network

This article is a step by step setup proceedures for windows vista networking

Windows Vista Help: Setting up a home network