ZoomIt

I hadn't seen this before, but a colleague returned from Redmond and mentioned it had been used to good effect in presentations he'd seen. Being a PowerPoint jockey, naturally I had to take a look.

ZoomIt provides really simple zoom and annotation capabilities when you're running demos, or technical discussion.

http://www.microsoft.com/technet/sysinternals/Miscellaneous/ZoomIt.mspx