Moving several products from one category to another is not a hard task in Magento and can be perfectly done through admin interface. But what if you need to move several dozens products? It’s getting much more time-consuming, boring and prone to manual error. With hundreds and thousands or more of the products manual approach is getting barely possible.
One of the solution is to use for that export-import functionality and the video below prepared by Steve Kukla from Magento University explains how to do it in details
As you see there is a downside with this method – it doesn’t allow you to move all product types, for example bundles have to be moved manually. However you can use similar approach with more advanced export-import tools that support bundles.