Anon,
What you want to do is actually not too tough if you're
using XP. You will need XP Professional on the machine
that has the connection you want to share. This machine
will also need two NICs.
Step one is to set up one NIC to use your high speed
Internet port. You'll need to set up the other NIC to
connect to the other computer. I assume you know how to
do these tasks: with XP its pretty simple.
Once you have this stuff up and running, go to the XP Pro
machine, log in as aministrator, Select <start>, <control
panel>, <network connections>. Right click the Internet
connection, select "properties", select the "advanced"
tab.Under "advanced" select "share this connection".
While you're there select "settings" and enable
everything you want to share.
This will reset your other connection (the NIC to the
other PC) to 192,168.0.1. If you're using XP on both
computers the other connection should autodetect using
DHCP; if it doesn't just reboot both machines.
There'a also a wizard which will do this for you.
Hope this helps!
Pat