All prices are US Dollars.
InterWrite Workspace software (free for users of InterWrite products and their students, 45 day trial available). Windows/Mac. Wonderful software for annotation & lesson creation. Buy one of their $399 wireless SchoolPads to get your entire school a license to their software.
SMART Notebook software (free for users of SMART products). Windows/Mac. Excellent annotation & lesson creation software but Smart's locking it all down with version 10.
Microsoft OneNote (<$100 for educators & students). For Tablet PC users and Windows users with graphics tablets. Very nice organizational tool which can serve double-duty as annotation software for WM making.
Blade Software's NotateIt (About $30). Windows 98 and after. Excellent annotation software. Version 3.0 includes screen recording and the ability to embed movies in NotateIt files.
Microsoft NetMeeting's Whiteboard (free) - Comes with Windows 98 and after. OK software.