Vista Services Optimizer?

While I have no personal knowledge of this program, these types of programs can offten create more problems then they cure for the inexperienced user.
If you are having a particular problem, it's best to get some advice on it on the forum.
 
A good palce to go to see what different services can be turned off is
www.blackviper.com

It is a good site that lists the services and their dependencies so as to not turn something off that is required.
@ things that I reccomend to be turned off are indexing and search. Both are resource hogs and you will see noticible improvement without them.