I was looking at some kinetic typography videos - like the one below - and wondering whether there is a plugin for Adobe After Effects CS4 that can help with this. If not, then is there any other easy way to do this?
As of 2011, there aren't plugins that assemble a typography video for you, because this kind of work is really a sub-topic of motion graphics. There are tools that can help you with camera animation and rigging in AE though.
My favorite is Video Copilot's Sure Target 2, which lets you think about the animation in terms of what you're looking at, instead of thinking about it in terms of camera perspective. This makes the work feel similar to using something like Cinema4D's target camera.
Another noteworthy tutorial: http://ae.tutsplus.com/tutorials/motion-graphics/design-rhythmic-motion-typography-in-after-effects/
If not, then is there any other easy way to do this?
TypeMonkey will help you a lot when trying to create kinetic text animations. http://aescripts.com/typemonkey/