We are looking to get the most bang for our buck, what is the best method for marketing our mobile application? Are there services that specialize in marketing for mobile applications? Any suggestions?
Difficult to tell w/o knowing more.
Find a direct competitor and deep search where they are - and then target the same media outlets.
Or - if you have $$$ go to an agency and have them do the above. If your product warrants it, gorilla marketing companies can offer non traditional media placement.
Use social networks, write your own blog and promote it, comment other blogs.Good luck!
For getting information on when and how people are using your app, I recommend Localytics' mobile analytics. Getting good analytics so you can better target & frame your marketing is key to cost-effectiveness.
AdMob is supposed to be good, and they were recently purchased by Google: http://www.admob.com/