I currently have an app named BART Fares in review for the the App Store.
A while ago, I coded a promotional landing page for Geometry Stash. You can get it here.
I thought about marketing it, not to a pc, but to the user when they were using the iPhone. The obvious choice was Apple’s iAd network which provided pretty much everything an advertiser would need short of the product. I’m still the process of doing such a thing. But why wait?