I am running two machines, both with Windows XP Pro. I want to try and do the following. Connect both PC's via LAN using TCP/IP. And then I want to try and share my internet connection so that with one single modem I can browse the internet on both PC's on the same time. Internet speed in this case will be irrelevant. Even if it is halved its okay. Would I be able to do this, and if so then, what additional software will be used to do it?
Andrew ;)

All you need is 2 lan cards and a cross patched cat 5 utp patch lead. Windows XP already has the capacity to share internet connections.

"Would the following be worth while?"

Of course. Lot of advantages. The first that comes in (my) mind is the possibility to make backups (using for example Ghost over the network you can backup the system of machine one to the harddrive at machine two...).
Lot of other good things too...

Thanks for all the replies. I've got the network cards. I think they're 10Mb/s one's. Thats fast enough hey? I'll try it out and see how it goes. :D