It is possible, first u connect your pc which is having net to Other PC by cross cable
and make the two pc as sharing mode and you can access net from 2nd PC.
It would be easier to use a network switch/router and connect them both to the internet source directly if its an RJ45 connection. Otherwise if you are on XP/Vista/7 there is internet connection sharing wizzard (ICS)
place 2 Network Interface Card in the PC which is directly connected to internet. in the second PC network Card getway will be your first PC network card address which is directly connected to internet. and in the first card you have to share the internet.