Here's the story of one libraries approach to that from a Code4Lib 
Journal article:

http://journal.code4lib.org/articles/2941


On 3/7/2011 4:24 PM, Rosalyn Metz wrote:
> Hi Everyone,
>
> I was wondering if you had suggestions for an online room reservation
> system.  I feel like people have asked this question before but I
> can't seem to find the thread.  I want something that people can self
> schedule themselves.
>
> Rosalyn
>