There are heaps of products around that pretend to be able to convert a presentation to video while conserving animations. However, you will never know if they can succeed on your presentation without trying them out, but luckily trial versions are ususally available,
Here is a quick and unverified list of some of them :
Microsoft PowerPoint 2010 can save a presentation as video. For details see this article.
If you don't have this version, maybe you know someone that can do you this service for free.Leawo PowerPoint to Video (free and pro versions, pro at $44.95, mostly good reviews)
Acoolsoft PPT to Video ($49.95, good reviews)
Presentation to Video Converter ($59.95, negative reviews)
PowerPoint to Video ($39.95)