I've made a little installer script for using the Evernote SDK in Pythonista:
Installer: https://gist.github.com/omz/5048588
Simply save this as a script in the root folder and run it. This will install the Evernote SDK and all its dependencies in a sub folder named "evernote-sdk".
To actually use it with your Evernote account, you need to create a developer token. You can do that here:
https://www.evernote.com/api/DeveloperToken.action
Copy the token to the clipboard and paste it into this demo script:
Demo: https://gist.github.com/omz/5048592
The demo shows a list of all your notebooks and then creates a new note in the default notebook. If you have an image in the clipboard, that image is attached to the note (as a png file).
Enjoy!