This is a wonderful app for keeping track of pgn-format games and databases for a small chess club. It allows you to save, search and view pgn databases and games. It includes a board.
Unfortunately, the download/upload function is, so far, purely copy and paste.
It is intended to work with google appengine, but feel free to use the files in other contexts.
Minor bugs:
Make certain there are at least two tags at the top (that is usually the case: 'White' and 'Black' is already two); otherwise, it will only save every other line.
Use latin characters (will fail with Russian characters).