The Google Adsense program now features referrals. For the time being, you get up to $1.00 for referring customers to the Firefox Browser with Google Toolbar, and if you refer someone to Google Adsense, and they earn $100, you get $250.
As a member, Google Adsense "referrals offer you a new revenue opportunity while increasing your users' awareness of useful products and services. Adding a referral button to your website enables you to generate additional earnings by directing users to download or sign up for products such as AdSense. When a publisher that signed up for AdSense through your referral earns their initial" $5 you will receive $5 and when they earn their initial $100.00 and is eligible for payout, we'll credit your account with $250.00.
Free Advertising with Adsense Revenue Sharing More About Google Adsense Referral