Attention to folks familiar with FM transmission

[Neil Joseph Schelly]

This message isn't Linux related - I'm sorry - but I know there's a lot of 
contributors here who are familiar with radio transmitters and the like.  
Please reply off-list if you can help me out.

A club I'm involved with has an interest in a small FM transmitter setup that 
can be used to extend a PA rather cost-effectively over a half-mile radius or 
so.  I think that can be done with a relatively low-power setup that can 
operate freely without tripping over other signals and the like, but I'm 
really not sure about the laws governing this stuff.  

Can anyone inform me what it would cost to buy/build such a setup and what 
restrictions there would be on its use?  Would anyone be interested in 
building that setup for me assuming the price is within our means?

Thanks in advance!
-N