Here are the only two that I personally use and will ever recommend. You can see my review on them here.
I'm giving away a free ebook at my website that hits this topic right on the head. Many people have told me they've had great success with the topics discussed in it. Check it out at Mbtmedia.com
If some one needs an ebook(not free fully--I just purchased) see thread http://forums.digitalpoint.com/showthread.php?t=1384171