Linky. Tile based games tend to be smaller in file size and therefore faster to load. They also are easier to create, as you will only need to make the code.
This is a great site on how to make tile games in flash. It has detail descriptions of every step to take and the source code as well. Its all coded in flash 5, but it's pretty easy to follow. It also explains the advantages of tile based games.
I'd recommended the same link as Soapaintnice above, a really thorough guide, although a bit of previous experience and intuition is needed to convert it to newer versions of AS.