You can get Xcode from the Mac App Store as a free download. From within that (in the preferences | downloads) you can download and install the command line tools.
You might also need to tell the command line tools to use the versions within the Xcode app bundle rather than those in /Developer which aren't there with the new package based install.
Run this from the Terminal:
sudo xcode-select -switch /Applications/Xcode.app/Contents/Developer
