Here's a list of programs you can make flash in. I suggest you start off with Adobe Flash or The Game Factory 2. Adobe Flash has the most freedom and you can make both games and movies with it.
This should help you get started in Adobe Flash. It has links to flash tutorials, flash and graphic software, API tools, etc.
To submit a movie/game you click the icon with the P on it at the top of the site and create a new project for whatever you want to submit.
If you need help with anything in flash you can ask in the flash forum. Or if you use The Game Factory 2 you can post here with any questions.