OpenBoard - The OpenBoard software is an interactive white board software.
Conceptboard - Instant Whiteboards for Teams & Projects
Microsoft Whiteboard - The canvas where ideas, content, & people come together.
Whiteboard Team - Draw, explain and collaborate visually in real-time.
NoteBookCast - A real time shared whiteboard in your browser, teach, explain, sketch. For work, study, fun.
Twiddla - Mark up websites, graphics, and photos, or start brainstorming on a blank canvas.