Lightspeed has done a little math on the iTunes app store and found that Apple made between $20 and 45 million on iPhone Apps so far. Their methodology took the total number of apps sold – $1 billion – and the average price of iPhone apps – about $2.65.

Multiplying this by 25-50m paid apps, that suggests that the cumulative revenue from iphone apps is around $70-$160m. Apple gets 30% of this so Apple has probably made around $20-45m from the billion iPhone apps downloaded. (Note that if you use an assumption closer to $1.50 for weighted average app price, then this estimate drops to around $12-27m).

It’s not huge, but I doubt Apple got into the app control business for kicks. An, when compared to the amount Microsoft and Nokia get for apps that run on WinMobile and Symbian – just about $0 – it’s a pretty tight deal.