cannot find zip-align when publishing app

I fixed it by installing Android SDK Build-tools 20:

In Eclipse → Pull Down Menu → Window → Android SDK Manager, check Android SDK Build-tools Rev. 20, then click the Install n package(s)… button to start installing.

I had the same problem. And to fix it, I copy the Zipalign file from sdk/build-tools/android-4.4W folder to sdk/tools/

Edited: Since Google updated SDK for Android, new build-tools does fix this problem. So I encouraged everyone to update to Android SDK Build-tools 20 as suggested by Pang in the post below.