30fps is plenty, and some animators use only 15 (although I can defintely tell the difference) and it looks relatively smooth.

It could be a great number of things:

1. Video playback on your machine ... i.e. it is being animated correctly, and encoded correctly, but your machine is not playing back your animations properly. (Can you post a link so that we can see what you are talking about?)

2. Encoding of the video. Or perhaps when you have the aniamtion setup at 30fps, but on output you are choosing something different?

3) Or, an actual animation issue, such as not using enough keyframes, or more than likely, you're using all Linear(or Constant, that would definitely make it jerky) instead of mostly Spline, or combination of Spline/Linear.

Look at your animation keyframes ... are they mostly brown, mostly green, or white/grey?

It's really hard to say without seeing the animation and/or your keyframes, etc.

-Tim