All of these networks are FREE to join, and by joining them you can get access to affiliate offers that other people. Affiliate networks allow you to access several affiliate programs at the same time.
Affiliate Fuel - I personally have made some good money with this one.
Adreporting - Also worth joining with a good variety of offers.
The largest four programs are: Commission Juntion , Linkshare , Permormics and Be Free
Here is a list of the other affiliate networks:
Some powerful affiliate programs to join
Subliminal PC - A great product which can be marketed across multiple categories making it easy to reduce your competition. Enjoying an enormous increase in popularity in all industries such as fitness, motivation, mental health, hypnosis, career skills etc... The list goes on, the product truly does appeal to a wide variety of consumers making its marketing very easy.
AllPosters.com - Top affiliate earns over $5,000 per month. Sells posters!
VMC Sattelite - Top affiliate earned $169,300 in one month according to their web site. Sattelite TV service. Note that this IS a believable figure because each installation pays $50 which means that this affiliate would need 3,380 installations in one month. Considering that there are over 200 million people in the USA, all of whom watch TV, and may want a satellite service which has more channels than cable and saves you money, this is believable. Their number 2 affiliate earned $46,000 and the no 3 affiliate earned $29,000 in one month.