From OS X Daily:
7. lipo
lipo (aptly named) is a utility that manipulates universal binaries in Mac OS X. A lot of (almost all) programs these days ship, or download as “Universal”, meaning they have binary code that both the powerpc and the intel chips can understand. But since you probably don’t care about one of the two, you want to use lipo to “thin” down your binaries. For example if you wanted to thin the “Stickies” application to only contain intel (i386) code:
cd /Applications
lipo Stickies.app/Contents/MacOS/Stickies -thin i386 -output Stickies.app/Contents/MacOS/Stickies.i386
cd Stickies.app/Contents/MacOS/
rm Stickies
mv Stickies.i386 Stickies
One I had never seen!