Last week, the IIS team released bit-rate throttling module to the web.
As the self-proclaimed daddy of the project (I designed and wrote the initial prototype in early 2007), I am very thrittled to see it out. The new IIS media team folks have done a great job getting it production ready and rounding out the feature-set, which you can review in its full glory in Vishal's post.
Although the feature is a bit different from how I originally envisioned it, it kicks ass at doing what it is supposed to do - saving your bandwidth costs. Read more about at http://mvolo.com/blogs/serverside/archive/2008/03/16/IIS-7.0-Bit_2D00_rate-throttling-module.aspx.