As an educator who teaches about education technology, I would suggest you search for lesson ideas in something other than Google or Yahoo. I recommend teachers use Delicious (Del.icio.us or Delicious.com) or Diigo.com which are websites for sharing web bookmarks and favorites. This is really catching on with educators who need to access their websites at school, home, or in training.
There is a search tool on these sites where you type in keywords for the resources you need. I don’t know about specific Lesson Plan sites anymore but if you are looking for resources on a particular topic or subject, this is a good start.
Other places to go would be NING (http://ning.com) which is where you can create your own social network resources. There are social networks in there for teachers on various subject areas. Join some of those groups and post questions in there. Imagine sharing a social network with new and experienced teachers on the subject you teach. Rich resources and networking available.
And all these are free. Good luck to you!