The easiest method I've found (and it seems others here as well) for sharing .capx files would be to use Dropbox. Here's more info on that in case you haven't gotten there just yet.
Upload your game to Dropbox
And for posting links to .capx files here, you can simply paste the link directly here, or wrap the url with the BBcodes. You can click on the BBcodes link below the reply editor to find more info on that.
That said, I threw together a quick .capx example demonstrating how to destroy the bubbles based on the player's bubble color, represented by the animation frame.
Basically, the sprite object's animation frames hold the various bubble colors. The Bubbles and Player have the same animations, but can be on different frames of the animation. When a collision occurs, a check is made to see if their animation frames are the same. They're both destroyed if so.
Here's an exported example: Bubble Pop Game Example
And the .capx: bubble-pop-game.capx
Hope that helps ya out!