If you are into Cost Per Action Marketing or planning to go into that area. Here's great big list of Networks where you can register and become a Publisher or an Advertiser.
AdFish
AdReporting
AdterActive
AffiliateCop
Affiliateer
AffiliateFuture
AffiliateWindow
AzoogleAds
BulletAds
CheckMyStats
ClickBooth
ClixGalore
CommissionJunction
CommissionSoup
CPAEmpire
CPAJunction
CPAStorm
CyberBounty
DarkBlue
eAdvertising
FileBreeze
FiliNet
FineClicks
FloppyBank
FluxAds
HydraMedia
InstantDollarz
LeadClick
LeaderMarkets
LeadHound
LinkConnector
LinkShare
ModernClick
Neverblue.com
OffersQuest
PaidOnResults
Performics
PrimaryAds
RevenueGateway
RevenueLoop
RexTopia
RocketProfit
ShareASale
ShareResults
Turn2Offers
WolfStormMedia
CX Digital/Incentaclick
Pepperjam Network
Amped Media
DirectLeads
AdValiant.com
Did I miss something? Feel free to add!
AdFish
AdReporting
AdterActive
AffiliateCop
Affiliateer
AffiliateFuture
AffiliateWindow
AzoogleAds
BulletAds
CheckMyStats
ClickBooth
ClixGalore
CommissionJunction
CommissionSoup
CPAEmpire
CPAJunction
CPAStorm
CyberBounty
DarkBlue
eAdvertising
FileBreeze
FiliNet
FineClicks
FloppyBank
FluxAds
HydraMedia
InstantDollarz
LeadClick
LeaderMarkets
LeadHound
LinkConnector
LinkShare
ModernClick
Neverblue.com
OffersQuest
PaidOnResults
Performics
PrimaryAds
RevenueGateway
RevenueLoop
RexTopia
RocketProfit
ShareASale
ShareResults
Turn2Offers
WolfStormMedia
CX Digital/Incentaclick
Pepperjam Network
Amped Media
DirectLeads
AdValiant.com
Did I miss something? Feel free to add!