Mobile Application - location based check-in

I am looking for someone to build a mobile app on my behalf, I would need to launch it on the iOS, Android and Blackberry when it is complete. I am just looking for costs at the moment to pass onto my client, I am a web designer and would like to handle the graphics and interface myself to cut costs if that is something you would consider?!?!

A brief out line of the app is that a user goes to locations and checks in and a database (I assume this would be web based) stores this information, there is a little more to the app but this outlines the technical aspects I would require

When replying to this could you please say 'DEAR MR REECE' at the intro, so I know that you have read this description carefully!

Thanks for your time!