Overall it is a good looking and fairly slick first pass at this. It would seem that you are on the right track for a simple account management system.

That being said criticism is the best way to make a product better so here are things that I would change:

1. Do not force the user to enter a dollar sign every transaction. If I want to say "10 sandwich" assume that because there is only one number that is the dollar amount. It does not seem like much but it saves two keystrokes for every entry. It's the little victories that make a user feel good about using the service.

2. Make the please wait windows go away. It is very jarring. That task should be handled in the background and updated via some Javascript.

3. Get rid of the flash and use a Javascript library for the graphs. Unless you are offering video there should be no need for flash.