First I looked at justin.tv but I couldn't find ANY information apart from some vague partner page, no pricing, no additional info, no nothing. Maybe I missed something, because we would be a semi-pro setup, not a regular Joe streaming his cat online. So I'm not sure if I could do this at all through justin.tv or not.
Then I looked at ustream, it looks great - there is embedding, there is ustream producer pro, etc... but prices are definitely out of our range. This is something we would do without profit and I may have a budget for it about couple of hundred dollars per year.