Online High Scores?

I'd like to have my game display a "world" list of high scores in-game. This would require:

A) Allowing players to submit their high score to a database on my website
B) Allowing the game to retrieve the top 10 from that list when they view the high-scores in-game.

I'm sure this has been done before... it's such a common thing for games nowadays. But I'm pretty sure it requires modifications to the engine, if I'm not mistaken. I'm just curious if anyone has such modifications they're willing to share or sell (I'd gladly pay $100 or more to save the time and not have to write the code, esp. if it were cross-platform), or can point me in the right direction if I need to do it myself.