We will get in the four figure a month income bracket by March 2007 with our blogs. Our main blog
Click A Life Coach - Personal Development and Life Coaching Blog currently makes a couple of dollars a day. Still waiting for the first cheque from AdSense to arrive as we haven't cracked the 100 dollar mark yet.
I tried an experiment the other day with a MLM blob I run as well and used Google Adwords for it. My AdSense income went up, but the money I spent on AdWords was much more.
Next step for us is getting involved in affiliate programs as they are better value than AdSense (so I think anyway)