The basic method I suppose is, a wireless router containing a modem. To this you attached 'power' & 'phone cable'. Each computer will require if not already fitted some form of wireless adaptor. If not you will have to fit them. If you don't fancy opening up your computer these will have to be USB wireless adaptors. I would suggest everything is the same make.
If you look at the PC Advisor 'search' there is a lot on this subject.
At least you will be back ^bump^