They have now posted their intention of changing the system even before Cataclysm launches.
In what way will it change? Not exactly revealed yet.
I can only assume it will be somewhere along the lines of the change they did with PVP BG Tokens: perhaps turn in your old Heroic badges in exchange for the new Hero/ Valor Points.
If you have no Idea what those points are you can go back and read about the badge system removal in cataclysm Here, and continue reading for the newest Blizzard update.
Existing Currencies/Badges in Cataclysm
We think it's fair to let you know what's going to happen to all of that old currency. It's not yet time for us to discuss that entire plan, but we'll do so in enough time for your to react.
Overall, you can expect that there won't be much motivation to hoard and even less to go out and farm old content in preparation for the Cataclysm launch.
We would definitely like to get some of that stuff out of your currency UI so you don't have to look at that lonely Badge of Justice for the rest of your character's career.