Wireless networking is not an option for the Amiga as the network PCI cards i have been looking at don't have a supported controller card.
If you are using PC's then its easy.
ASDL modem into a wireless router.
Wireless network card in each PC.
Would at current UK prices set you back around £180 but stuff is cheaper in the states anyway.
Anymore than three conversations (2 pcs and a router) and your going to need a wireless access point.
This way you only need one cable connection and you can have a network as well.