How do you share internet connection from a PC taking its connection from a switch to another PC. The PC that will be sharing the internet connection has 2 NIC's. How do i connect to the other PC with the second NIC in my PC to the other PC that is not connected to the switch giving internet connection.

Kind of depends on how you access the internet. If the switch/router/modem is the connection point you may be able to do a different setup or change your config to allow the point of connection to be the modem/switch/router. One way is to use ICS built into XP. See help and support center for how to. Also many web pages. I prefer to use Analogx's free proxy. See the readme file in download. "Best Practices", Event viewer, host file, perfmon, antivirus, anti-spyware, Live CD's, backups, are in my top 10

If you do not use router, check whether this Internet Connection Sharing tutorial can help you.