I made a bit of a resource guide to the Indy 500 race online:

Indy Live
IndyCar Race Control presented by iRacing.com
On your station starting at 12PM ET
The 1961 and 1962 Indy 500 on RaceFansTV.com: First time 150mph was broken. A must watch!
Live Radio Streaming
Official Twitter feed of Indianapolis Motor Speedway
Danica Patrick on Twitter
Indianapolis Motor Speedway on Google Maps
Interesting facts about the Indianapolis Motor Speedway from the U.S. Census (pdf)

...

Please add more!
Feel free to post this elsewhere