What operating system do you have on your PC at home? If you're running Linux, or some other Unix variant, then Mediatomb is a great piece of software for streaming video over a network to other PCs. It just streams the whole file, then the client decodes and plays it itself, so it should work fine with whatever format you throw at it. The downside is there's no Windows version, and I can't think of any other equivalent software for Windows. You might be able to get it running in a virtual machine or something though perhaps.
As for the network speed, if it is actually 10Mb/s, then that should be plenty. But since it's ADSL, it might well be significantly less than that, depending on the line, distance from the exchange, etc, in which case it could potentially be problematic. The only way to know for sure is to test it and see.