Tools to save click through data in a search engine

[rr...@gmail.com]

hi all,

I am using lucene + tomcat to host a web search engine. I want to save the
queries posted to the search engine and the clicked results
returned by the search engine. However, i am unsure if they are any tools
readily available to do that (prefererably open source tools)
I am sure atleast some one in this list might be doing it. Could you please
point me to any sources avaliable.

thanks
~Rsh