Student Web-based Presentations

I am seeking ideas for having students give presentations electronically. My ideal would be for students to post an electronic presentation in a secure spot (no public access without an invitation to view. I would then like these invited visitors to have the capacity to comment on the presentation and to ask the student questions - asynchronous. The visitor should be able to choose whether their comments and questions were visible to other invited guests or only visible to the student (and professor). I am a novice at this. What techniques do you suggest? What software, etc. do I need to investigate? What advice do you have for me?

YouSeeU.com

YouSeeU.com is a service designed specifically for student web based presentations. I'm using it for online business communication.

VoiceThread

You might want to look at VoiceThread. I think it will meet your needs: http://voicethread.com

New Life Cleanse

student are developed the web based presentation for campus New Life Cleanse New Life Cleanse