Design Application

Question

Hey everyone,

I am planning an application to do the following, and i would like some ideas of where to start and how to work with different aspects of the program for example saving and stuff.

Pretty much when the user creates a new document, they will get a pre-drawn shape i will use a square for the example. The user can then import images on top of this image and free hand draw and text and stuff. If they want to remove anything they have added they can but can't remove the pre-drawn shape.

I am thinking about layers maybe this could be added later. I really do want to create my own file type that only my application can open. this would prevent the default shape from been removed as this is critical.

If someone could please help me with some ideas, websites, tutorials, books or anything i would appreciate it. I am a website programmer in asp.net 2.0 and c# i am more than comfortable with c# so please don't be afraid you will scare me away.

Cheers
Regards Daniel