Easily Sign APKs and Flashable ZIPs without a PC
If you like to theme or otherwise modify your mobile apps, you have surely had to sign a fair number of APKs in order to then install them to your device. Unfortunately, though, this typically means having to use your PC. Normally this wouldn’t be a problem, but if you wish to do a bit of app modification on the fly and away from home, this could present a little bit of an issue.
Thankfully, XDA Senior Member thewarlord briefly outlined the incredibly simple steps required to sign both an APK and a flashable update.zip from the comfort of your mobile device. The guide is split into two parts: one for APK signing and one for update.zip signing. The process for either involves using the freely available ZipSigner app, and selecting the proper options. And if you also need to decompile and recompile your app on the fly, you are instructed to use the open source APKTool for Android.
Road warriors should head over to the mini-guide thread to get started