I am doing a 3-day online instructor-leading training class this week. I came across this good article that has lots of helpful tips.
Learning to use web conferencing technology is pretty easy, but there is a lot more to training via web conference than just putting on a headset, dialing up an audio-conferencing bridge, and logging onto the application.
Check it out: http://www.syberworks.com/articles/28-Web-Conference-Training-Tips.htm