Most of these come with a free trial so you can try their features before shelling out the cash.
Authorstream: Any video lasting longer than five minutes requires a premium account that charges $2 per video credit that equals a file up to 1 GB in size or 45 minutes in duration.
E.M. PowerPoint Video Converter: Converts videos without watermark and no registration reminders.
PowerVideoMarket Professional: Preserves PowerPoint presentation's animations, transitions and narrations when converting to AVI or MPG format. Retails for $149.95.
Presentation to Video Converter: Converts PowerPoint presentations into AVI, MPEG and other video formats. Retails for $99.95.
PPT2DVD: Burns PowerPoint to DVD and adds menus to play the DVD on TV. Retails for $99.95.
PPT to Video Scout: Converts PowerPoint presentations that have animation and sounds into a video while retaining the effectives. Retails for $69.
As always, have your antivirus application running as we can't guarantee these applications are free of spyware or viruses.