Help with wireless internet sharing please

[Teasy]

Two of my friends want to share a ADSL connection. They live almost directly opposite each other (can't be more then 20 feet appart accross a small bit of grass). What is the best option for doing this and how is this kind of thing setup in windows? Any guides you could link me to and any products (access point/antenna) you can suggest would be greatly appreciated. Cost is a big issue BTW.

Thanks

 

[tolien]

One ADSL router (probably wireless), and some kind of wireless device at the other side.
Probably need better antennae too. Windows setup isn't going to be any different than with their own connections.

Biggest issue I'd be wary of is whether the ISP is fine with the idea of sharing it with someone else.