Any Mac-based JustinTV users?

[bulgariacalling]

Hi Folks

I've recently created a new web site for a client that's a few hundred kms away from me. I've created a series of very basic training videos so I can take them through the admin side of the site, via the videos, but also on Skype-cam at the same time (don't panic, this will be on a sandbox site, not a live site!).

I was thinking of using JustinTV to 'broadcast' the videos to the various staff members, wherever they are (they also have staff in other countries), at set times every week for the training sessions, until they (well, me to be honest!) are confident they can be let loose on the live site.

I've created a Justin account, created a channel, but can't for the life of me figure out how I can broadcast a video that I have playing on my desktop.

Has anybody done this on Justin? If so, could you let me know (in very simple steps) what I need to purchase in order to make this work, and how to make it work!

Thanks in advance