One thing to be careful of here. If you intend to implement the idea (rather than just patent it) doing the search puts you at risk to some degree. If you do the search yourself (possibly not finding the relevant patent) and then do the implementation anyway, you are at risk for "willful infringement". This is all really murky and you probably want to talk with an attorney if you are serious.

Link with some relevant info: http://wistechnology.com/article.php?id=1303