I Have set up my internal network using a DWL-2700AP > Outdoor 2.4GHz (802.11g) Wireless Access Point
http://www.dlink.com/products/?pid=303 which is a wireless access point using dhcp from the sme server for people that come with their laptops i request the mac address of wireless card and then give them a hex key to access the network once they leave i remove the mac address from the allowed list and delete the hex key. It works great for me very easy to set up.
Also I have just had a client who owns a bed and breakfast establishment to set up a simlar system for him he is going to set a fixed fee to access the internet through wireless using the sme has is firewall and to serve is static website and booking service.
I found this to be the easy solution to wireless with the sme server.