hello. it is possible to do, relatively easily. sharing an internet connection would be out of the question as far as i know anways, ive never seen a wireless router that was compatible w/ dialup. first you need to buy a wireless router, personally i like Linksys (but thats only because Cisco owns it :P) you will need to set that up in a central location and configure it. You can use it as a DHCP server, or just use static address, either way will work fine. I would reccommend applying mac address filters. You will need to go on each computer and go to start>>run>>cmd and type in "ipconfig" w/o the quotes. it will tell you the mac address, write it down and then you will enter all 3 into the wireless router.
You will need to purchase 2 pci wireless NICs (i would recommend sticking w/ the same brand as your router, that typically works best) and install them i the pcs. From there is should be gravy.
Depending on how big your house is you might need a wireless extender, or AP set up as a repeter. The other options is if you are concerned about signal strength you can get a pre-n router, but they get somewhat $$$, but promise wider ranges and faster connections. check this out:
http://reviews.cnet.com/Belkin_Wirel...-31489123.html
for sharing the printer... you can either set up a print server, or if the pc it is attached to is always on anyways, you can just leave it attached to that pc and go to control panel>>printers and faxes>>right click on the printer>>sharing>>then select "share this printer" and give it a name. then on the other computers go to add printer>>from network>>find now>>and add it. please let me know of any other questions, or if i was unclear. and if anyone see something i said wrong, or missed please correct me
-Daem