Multi user broadband

[John]

My PC at home is connected to broadband but trying to get to use it is almost impossible as the kids are constanty monopolizing it. So I am buying each of them their own pc that they can use exclusively in their bedrooms (something tells me they may have planned this).But unless they have internet access my cunning plan falls apart.
So could anyone help me with the following:
(a) is it possible to connect more than one PC to a home broadband connection?
(b) If it is possible can everyone be online at the same time?
(c) The home PC is plugged into a telephone socket using a splitter that allows the phone to be used at the same time as being online, will this be compromised?
(e) There are no telephone sockets in the kids bedrooms, so would I have to hardwire these in?
(f) can the extra PC's be connected cheaply and easily?
(g) what exactly will I need and how would this be installed?

Many thanks for any help