ActionScript 3.0 :: Softwares To Create Youtube Style Annotations?

I'm working on a guitar tutorial website where users can select parts of a song, then write an explanation of how to do that guitar technique. The explanation will pop up, like a youtube style annotation whenever someone plays that song. It's like the youtube video annotations, except exclusive to guitar lessons:When someone plays a song, the annotations get displayed in real time.-There will be 3 sql databases: user information (ex. email, password, etc...), song meta information (ex. song name, length of song, etc...), annotation information and content (ex. annotation start and end time (to queue when the analysis/annotation should be displayed), etc...). The flash gui will interact with all databases.There's a lot of options out there (Adobe flash CS5, flex, flash builder), what are the differences between the three?