Can I run Xcode 3 and Xcode 4 at the same time?

I just upgra开发者_高级运维ded to Xcode 4. I have a project that is still dependent on Xcode 3. How can I re-install Xcode 3 and not screw up my current Xcode 4 installation?

No problem - the Xcode 3 installer lets you select an installation directory - my preference is to install it in /Developer-old for consistency with the earlier Xcode 4 installers, but you can put it anywhere you like, perhaps even create a subfolder inside the Xcode 4 installation folder for Xcode 3.

install it into another directory.