Found this site, where you can simulate a full indycar season or just the indy 500. Pick your team, make adjustments on your car, set your race strategy and compete against other online participants. There are other series that you can participate in as well, like F-1 and V-8 supercars. I think its pretty neat and I promise it is free, there is a 20$ add-on that is optional. No pop-ups and other annoying stuff. trust me its worth a look.
http://batracer.com/-1FrontPage.htm?Q4r
I've started a Private Game that is only open to invitations.
It is a full 2008 Indycar season post-merger-unification-buyout-whatever
Feel free to join only if you plan on seeing it through till the end.
Game number 36162
password indy500
Even if you don't join my game the site is worth a look.