Well now you can with the Web Developer Project Estimator. It a hosted service that is free and allows the developer to quickly punch in hourly rates for each task and have it calculated on the fly. If the default listed items are not tasks you would do, simply delete them and add those that are relevant to your development process. Once you're done simply click "view estimate" and you are good to go! As simple as that.
I give the Web Development Project Estimator a 4 out of 5. All that's left for it to get another star is the ability to download or e-mail estimate as PDF to client.