I am trying to set up a home network but there seems to be very little hard and fast info out there. The two computers are 25m and one flight of stairs apart. Do I get a wireless router etc, (what kind of distances can they handle) or do I conect two pieces of network cable together to link the machines(will there be any signal problems over this distance) Also I understand I will need a router as I have a dynamic ADSL IP address, is this correct.
A cabled LAN would do the job fine. The standard maximum distance is 100m, so no problems there.
You need a NIC (Network Interface Card) in each system, a crossover wired cable, and then you install internet connection sharing (as well as any file/printer sharing you want). Total cost under £50
Or if you want to spend (a lot) more and get more flexibility - you can do the same by wireless. Then you will need a wireless router/modem, and a wireless card in each system. Total cost probably in the £200-300 region.