There is a whole thread dedicated to that. Pay attention to the warnings/advice in the thread. Voodoo is more involved and from what I have heard, easier to cause issues to your phone if you are not experienced and comfortable with flashing roms, patches, etc. Here is the thread:
Even the people who are big voodoo fans will tell you the speed increase with voodoo is barely noticeable. For someone who is new to rooting and flashing, the problems you may encounter are not worth it when you probably won't see a noticeable difference in speed.