You can use QuickLookAPK, a APK Quicklook plugin.
It's actually a wrapper of the aapt tool @t0mm13b mentioned.
To install:
Download QuickLookAPK.qlgenerator zip file, unzip and put it in: ~/Library/QuickLook.
run
qlmanage -r;qlmanage -m
Now press "space" keyboard for selected APK file in Finder, view the AndroidManifest file info.