Xcode 4 beta not working

I downloaded and installed Xcode 4 Developer Preview 6 (January 10, 2011 / Build: 4A251a ) After the installation i see my old version 3.2.5

any idea why this is not working ?

cheers endo

EDIT: My 开发者_StackOverflow中文版solution was to fully uninstall Xcode then install the xcode 4 Developer Preview

sudo Developer/Library/uninstall-devtools --mode=all

Have you tried removing the old Xcode before installing the new one? Also, did you move the Developer directory from where it was originally located?