I have been asked by a couple of teachers to share how I provide instant feedback to my students. Its actually pretty easy with the right tools. My school uses Google Apps for Education, but even if your school doesn't you can still use these Google applications to send results to your students instantly!
Because I find videos easier to follow when I'm learning something new, I recorded a short (under 5 mins!) screencast showing step-by-step how I install and set-up FormMule to send students results to them.
In this video I will be sending quiz results, but in the past I used it to send results of major projects and other assignments. Its a handy tool to have in your kit. I hope you find this video helpful!