Strip x86 code from fat binaries
Wed, Aug 17 '05 at 8:51AM PDT • Submitted by lincd0 
Developers are starting to distribute binaries that will run on Intel-based hardware as well as PowerPC Macs. This will add about 30% to the size of the executables. To recover the disk space, you can remove the unneeded code using the command-line program ditto. 

For example, suppose is a fat application bundle installed on a PowerPC Mac. While logged in as an admin user, you would open a Terminal window and type something like:
ditto --rsrc --arch ppc /Applications/ /Application/
Now you have a new application called Test it. If it works, you can delete the original and rename the stripped version. To strip PPC code from binaries on an Intel Mac, you would change --arch ppc to --arch i386 in the above command. 

In case it's not obvious, keep in mind that this operation is not reversible. Once you strip the code for a particular architecture from a multi-architecture executable, it will no longer run on that architecture. So keep a backup copy.