Yes, you can add time between frames, but not as directly as you're used to in Flash. Here's an example. You've got a bouncing ball animation that starts on frame 1, hits the floor on 5 and gets back to its peak at 10. If you want to add two frames of space between the start and the floor hit: a)increase the animation range from 10 to 12,
pick the ball and head to the graph editor, c) marquee select they keys from frame 5 through 10, d) in the upper left hand corner of the graph editor there are two data fields (time and value) in the time field, delete whatever number is there and type
+=2 then press enter. This will move all the selected keys two frames forward in time. You'll still want to take a look at the curve tangency to see if it's giving you the look you want. Hope this helps.
-JP