The launcher on this page supports BOTH manual profile creation and a modpack distribution platform (one of the first!), but it is NOT updated for Minecraft 1.6.
However, because I still run a modded server, I still need a launcher, so I wrote a Minecraft 1.6/1.7/1.8+ compatible version. UNFORTUNATELY, you can't create your own version profiles in it. It ONLY contains the modpack downloading platform.
If you want to use this new launcher, you can find the source code on GitHub. The distribution platform works pretty much the same way as the one in this launcher (with the same features).
-March 17, 2014
This is an easy to use Minecraft launcher written by myself, author of WorldEdit and more! It supports downloading custom modpacks, makes mod installation easier, lets you change Java and memory settings easily, and more!
It's also OPEN SOURCE, so you can download the source code, edit it as you please, and make a new version.
1.6+ IS NOT YET SUPPORTED. I'm working on it. - Oct 21, 2013
Windows .exe (WARNING: You might get a .exe warning. Please ignore it or use the JAR instead.)
Mac OS X .app
Linux .jar (cross-platform version)
Find the source code on GitHub.
Talk to sk89q on Twitter.