I have been using Ustream for a small adult education startup for about a year now. Great service and all, but the delay to end user is become unacceptable. It's about 25-30 seconds.

My plan is to have a embedded player and "live talk" window developed on a secure part of our website where distance-learning participants (about 50% of our students) can talk live to the lecturer being recorded.

Where can I find or create a livestream/video stream mechanism with little delay (3-5 seconds max)?

Been streaming for a couple of years and my sense is that latency is something we just have to adjust to for now
Bottlenecks can occur anywhere out on the net.
I'm aware of 20 minute latency situations on some of my events

Wrong tool for the job.

If you need low latency, you need video conferencing not web streaming.

I use Webex sometimes from legal depositions for lawyers in remote locations. Works great. Runs on Cisco hardware/software, super service, needs Adobe Connect, minimal install on your PC.

Cisco WebEx Web Conferencing, Online Meetings, Desktop Sharing, Video Conferencing (http://www.webex.com)