RaceFansTV membership a whirl. This site, which has regular racing programming available also for free, provides on-demand watching and higher video quality for $5 a month. I'm going to give it a shot, and so far I like what I'm seeing, they're going to have to bump up the IndyCar and Indy 500-related material. Part of the issue is that this is a legal site, which pays for the races and documentaries they use, which means you aren't just going to see someone's bootleg tape of the 2010 Kentucky Indy 300 on there.
In the meantime, they do show some wonderful old documentaries of the '61 and '62 races, and the documentary channel overall is great. I also get some use out of the Rally & Offroad Channel. Still, I hope they figure out a good way to get more old USAC, CART, IndyCar, and Indy 500 shows up, because that's what's going to determine if I stick around.