Hey Gheatza,
The Media Foundation forum probably isn't the right forum for your question, since Media Foundation for Windows Vista will not have the support in-box that would be needed to source a live AVI-format presentation.
That said, if you were so motivated, you could try to write a Media Foundation Media Source that is capable of sourcing a live AVI presentation; however, this is probably more work than you want to do. DirectShow is probably a quicker route for something like this today.
You might want to try posting your questions in the DirectShow forum and seeing what you get there. Good luck!