I’ve  just found a great article which as a whole list of alternatives to Google AdSense, here’s an extract from it:

Google AdSense is the leader in web-based content-sensitive marketing.

Webmasters place Google AdSense JavaScript code on their web pages and Google AdSense serves advertisements based upon the content of the web page.

There should be a Google AdSense skyscraper displayed on the right side of this web page right now.

Some webmasters are either not accepted into the Google AdSense program, or do not wish to do business with Google.

For those webmasters, there are many alternatives to Google AdSense:

• Yahoo Publisher Network
• Clicksor
• TargetPoint
• MarketBanker
• BidClix
• Chitika
• AllFeeds
• Adhearus
• AffiliateSensor
• Bidvertiser
• Veoda
• Revenue Pilot
• Kanoodle Bright Ads
• Enhance Interactive
• Quigo AdSonar
• Searchfeed
• Vibrant Media IntelliTXT
• Vibrant Media SmartAd
• Nixie
• MIVA AdRevenue Xpress
• Fastclick
• contextWeb ContextAd
• TargetFirst
• CoverClicks
• AdBrite
• Rydium
• Claxon
• ClickThruTraffic
• ClixGalore
• Clickcent
• DynamiContext
• AzoogleAds
• Casale Media
• Burst Media
• Tribal Fusion
• Right Media
• RealTechNetwork
• Buds Media Network
• ValueClick
• Mamma Media Solutions
• RealCast Media
• Hurricane Digital Media
• Advertising.com
• adagency1
• Traffic Marketplace

AdSense Alternate Ads

Many webmasters are not looking for a true replacement for Google AdSense, but instead are seeking for an alternative for when Google AdSense is not able to find an advertisement which matches the content of their web page. Normally, when AdSense is unable to find a matching advertisement, it selects a random Public Service Announcement (PSA) and displays it in the ad space. These PSA’s generate no revenue for the webmaster.

Google has created the ability to load an alternate ad when it cannot find a matching ad. This is accomplished by setting a variable called google_alternate_ad_url in your AdSense layout code:

google_alternate_ad_url = “/adsense-alternate-ad.shtml”;
These alternate ads can include advertisements from Google AdSense competitors.

This capability enables you to tap into a revenue stream which would normally by lost to AdSense PSAs. It also enables you to test Google AdSense alternatives in a reduced-risk environment.

Now that’s only a selection of what the site has, and I’m not sure how up to date the site is as it dosent have sites like oxado which is a fairly new PPC Site but as you can see from the list it does have loads of others so I think it’s very worth while checking out.

Article found here.