I have used Google AdWords in the past to specifically target the content network on mobile sites with moderate success. The key to the best results is having both a product/service which is suitable to those who are browsing on a mobile device and also having a site which is optimised (aesthetically and accessibly) for visitors on mobile devices.
It's very easy to set up mobile specific campaigns within AdWords but the CPC's are not close to being as competitive as the ones which are listed previously within this thread.

Try Inmobi...

[DELETED]

1. Yes you can exclude mobile. It's under campaign settings --> devices. You can choose Desktop/Laptop, Tablets, and Mobile Devices (phones). I never exclude mobile in campaigns because after using the Google report function the conversion cost and cpc has been cheaper for mobile. Tablets are okay...

2. Yes you can only target mobile. Same place, just uncheck the other two options.

Mobile clicks are generally cheaper in the long run, but you should still set an initial bid on par with your computer targeted campaigns on Adwords. If you aren't in the position 5 or higher your results won't be very good.

My only mobile experience is with AdWords and the competition and cost-per-click is a lot less than regular search or display.