Strip Generator

Strip Generator

http://stripgenerator.com/

Quick comic strip tool for storyboarding.

Skitch

Skitch

http://evernote.com/skitch/

Mobile sketching and annotating app with Evernote integration.

POP

POP

http://popapp.in/

Mobile prototyping app for building simple functionality with hand-drawn sketches.

Wacom Inkling

http://www.wacom.eu/index2.asp?lang=en&pid=9226&gm=4

Clip-on device for converting hand-drawn notes to digital files.

Balsamiq

Balsamiq

http://www.balsamiq.com/

Sketching tool for rapid wireframing.

Paper

Paper for iPad

http://www.fiftythree.com/paper

Virtual notebook sketching app for iPad.

iBrainstorm App

ibrainstormapp

http://www.ibrainstormapp.com/

Virtual post-it/sketching app for connected iPhones and iPad.