Brokering your own advertisement deals
You may have good luck setting up your own advertisement deals. I know some who have been able to sell banner space directly to merchants at a fixed rate per month. If your project is in the right niche this may be a good way to go. I've heard of rates all over the place, from $50/month to $2k/month -- of course the amount you could charge is a factor in a lot of things including traffic reach, and advertising placement. You will be able to charge a lot more for a banner on the index page than something buried deep down in your site.
Another approach you can use in managing your own ad space is to charge on a per click basis in the spirit of Google's Adwords or Yahoo Publisher's Network. You will need some sort of tracking mechanism, but you are a programmer after all, so this task should be trivial to you. What rate should you charge per click? What ever the market will bear. The very bottom these days seems to be 5 cents a click, with the upper end being several dollars.
Though many have had great success managing their own advertising network, I would not recommend it to you as your only source of advertising income. Your reach to potential advertisers will be a fraction of what the big companies could bring to you. Give it a go if you are so inclined, but do not have this approach be your only advertising option.