Did a quick test of Apple's Smoothcam effect in FCP6.
I just did a quick walk around the backyard here with a camera. Just holding the camera by it's handle so I knew it would be pretty shaky. You can see how much it zoomed the image in that clip. But overall, I am very impressed with the effect. With a little planning, you could easily make a walking handheld shot look like it was on a dolly.
The clip was about 2 minutes in length and took about 30 minutes for FCP to analyze the clip. Add another 10 minutes for rendering in the timeline (optional). This is on a MacPro quad 2.66ghz machine with 5GB RAM and the scratch drive is 10K RPM RAID 0 setup.
UPDATE: I should point out here that if you are going to try to simulate a dolly using SmoothCam, you should really try to hold the camera as steady as possible. Smoothcam, as with all of these types of technologies will require that the footage be zoomed in slightly after the effect has been applied.
Obviously, you are going to take a hit on the quality of the image. The more zoomed in the shot is, the more of a hit that you will take. So, the steadier the original shot is, the less that it will have to be zoomed in and will mitigate the quality issues that you will have to deal with.