radiusserver for hotel hotspot

Somebody gave me a demonstration of a smc wireless hotspot gateway
http://www.smc.com/index.cfm?event=v...N_BEL&pid=1377

it worked with a radiusserver and he made an internet interface so that
we could give users the right to log in for a certain amount of time,
or until a certain date, or untill a max of download/upload was made

so more or less the same as an hotspot but with more possibilities

Problem is : they went bankrupt and were not able to finish the project

Could anybody help me with installing a radiusserver + making the
internet interface or does anybody knows any system that allready
exists

I will be glad to pay for it

Guy
www.coenen.be