Gyro Sensor Questions

[sanddrag]

I have a few questions about gyro sensors. First off, while browsing the Parallax site I found this http://www.parallax.com/detail.asp?product_id=28017 This is a gyro sensor right? I need something that can balance a personal transportation vehicle (on one axis) in the configuratuion of two side-by-side wheels. Will this do it? it says it will measure in the range of + or - 2 g's. Is that enough. I guess what I'm not understanding is how the terms gyro, angular rate sensor, and accelerometer are related or unrelated -- will someone please explain it to me?

Also, what happens if say this is balancing a vehicle and there is a lot of vibration or bumps in the road. Will this cause jerky throttle or does it know the difference between vibration and tilting? Would adding another sensor and taking the average reading help this problem if there is a problem?

What I want is to make something that does this: the more the machine tilts, the more it tries to compensate, like a segway I guess.

Thanks in advance for your help with this topic that is so new to me.