Is there ANY way to do this?

Ok i am living with my sister,and finally after a year i may be getting a room of my own(her daughters decided they wanted to share a room),but we have mostly been using wireless in the house,and i was hoping to have at least 2 pc other than my rig hook up to internet(a htpc,and a data server),but i only have 1 wifi adapter,and can't afford to buy another one,those other 2 pc are built out of parts i had lying around.

Is there any way to share the one wireless connection with the other pc's?

Like could i make a pfsense router(i have enough extra parts for that),and have it take in the wireless signal,and use wired connections to connect to the pfsense router?

the pc's would be on the next floor of the house and 20 feet over from main house router?

or is there another way?

If you're using windows, I believe on the PC with the wifi card you can go to your network adapters, open the properties of the wifi adapter, go to the "sharing" tab, and check "Allow other network users to connect through this computer's internet connection." I believe you also have to have general sharing checked over the local network, but then you can just connect the computers through their ethernet ports.

Though that might be a problem if you only have computers with one ethernet port, and you don't have an ethernet switch. Also I'm sure it will be far from great performance, but it's the only thing I can think of offhand.

So i could have the wifi come into my rig,and hook a ethernet cable to a switch(i have a few just got to find out which ones work)then cables going from the switch the the extra pc's?

Yes, that should work. Some of my friends and I have used it at LAN parties.

Edit: I'd first make sure that you can get the other two computers to first detect the main computer with the wifi card over the network, and vice versa, before sharing the connection.