There are many... this one does a nice job for me and generally finds more than most. It's a free beta but do not let that fool you. I have used the previous beta versions and never had any problems... this last version is simply and improvement on the previous beta. Get it here:
Best of luck. I am sure others will give you additional favorites.
I tried registry mechanic and it is awesome. I just need for someone to recommend to me a decent registry cleaner that is free. Any Ideas?