How do I repeat frame 2's animation again on frame 3?

I have an object with a rotation and location change between frames 1 and 2, how do I duplicate that animation between frames 2 and 3 and again between 3 and 4 and so on?

In the IPO window, select the right curve (or press A if that’s all there is), and do Curve>Extend Mode>Extrapolation. You can try some of the other extend modes as well.