I'm getting HDTV lust

Between Rich’s posts and the incessant promos for Comcast HD during morning drive time on KJR, I am starting to lust for HDTV. Some questions I have — when will DirecTV HD availability catch up to Comcast? When can I get HDTV Tivo? Are there such things as HDTV-encoded DVDs (I am aware this is a somewhat mangled expression of the idea) and where do I get them and what players play them?