MCVersion-Control is a program used to switch between different versions of Minecraft more easily.
Still in development phase, most basic features are implemented. Hope to roll out v1.0b in a week or so, once the update manager is complete.
Minecraft Version Control is under an Open Source license.
v0.1.1b - Fixes minor bugs v0.1b - First beta release v0.2a - Porting source to new design pattern v0.1a - Initial source
I hope to eventually convert this to a mod manager, that's far down the road though.