Hey Showbaba,
Emailing you offline kind of defeats the purpose of a forum to share info which is why I am posting here. The system will drop you a email letting you know I replied.
What operating systems are you running? Need to know the make and model if you will like XP Professional or Windows 7 Home, assuming it is a windows environment.
Does only one computer have internet connectivity right now? Does this computer have one or two network cards in it? Do you have the computers networked, meaning do you have a ethernet cable running to each computer from a switch and does each machine have a IP address?
Sharing printers is pretty easy scanners can be a problematic if they are desktop ones. If you get the answers to my previous questions I might be able to point you to some information that will help.
But to answer your question I haven't heard of any third party software that makes this easier, and I have been in the industry for 12 years. Windows 7 simplifies this a bit with HomeGroup, which is a peer to peer network.
If you don't have Win7 you can setup a little peer to peer network to meet almost all your needs.