Thanks for all the feedback. I will try to explain a little more detail.
The point of the project is two-fold: 1. use HD-SDI equipment as a pilot for a much larger project, and 2. provide live webcast (at a decent quality but not full HD) of multicamera events.
Right now, I use Windows Media to stream NTSC signal. I thought I would be able to convert HD-SDI to HDV and stream with Flash Encoder. Turns out HDV is not something that either WME or FME want to handle (will Wirecast injest HDV for a stream?)
So, is there a small-PCI card for HD-SDI and some software that will encode live to a viewable speed/size? Or is there software that will live encode i.Link from a Sony PMW-EX30 for the stream?