I get asked this question all the time, e.g. how to get started. It's simple really. Here is a step by step.

1. Come up with an idea. Sounds like you already have that.
2. Simplify your idea to its basic core - something you think you might be able to tackle
3. Layout the UI on a piece of paper or napkin, whatever.
4. Try and layout the UI in your development environment.
5. If you encounter difficulties, google, google, google, ask questions on stackoverflow, use the living crap out of internet resources to get help. Ask friends and co-workers who are programmers to help you with specific situations. Go back to step 4.
6. Start writing the logic of your application. If you run into difficulties, go to previous step and try again.
7. Soon enough, you'll have something working soon.