Just did a quick google search and although the link im going to give you is from our F1 2011 threads, its still extremely useful with links to various sites.
I believe the only major app at the moment is the rev counter/display.
Thing is Codemasters tends to change their coding alot so if someone made an app for f1 2011 it would have a good chance of being non working in f1 2012....
Where as the likes of rfactor and iracing have been around for a while and the coding rarely changes....