This handy little script has been created by Paul Jaruszewski whose web persona is Melor, which is certainly much easier to pronounce than Jaruszewski and consumes less bandwidth. 
Autocrop is used to crop an image that has been rotated. The script works out the largest rectangle that can be saved from the tilted picture that is the result of an image rotation to fix a slanted horizon, or crooked vertical. How many times do you get those with the tiny 10D viewfinder? 
The script is simple to use and works in both PS7.01 (provided the scripting plug-in has been installed) and PS CS. Download the script and copy it to the ..\Presets\Scripts folder.
Run the script after you have rotated in image. The only thing you have to worry about is making sure the background colour is different from the picture colour at the corners where the script does its work. Autocrop works out the edge of the picture by comparing colours. If you have this problem, then all you have to do is repeat the rotate after selecting a different background 
colour.
Paul and I have collaborated to produce an updated version of this script. This uses the new UI commands in scripting, so will only run with Photoshop CS.
Apart from the interface the significant change is the option to choose different search method. For small rotations - under 1-2 degrees - the "Pixel Slice" method will usually be fastest, otherwise we recommend using the "Binary Search" method.
As we've already noted the one situation (at least, that we know about ) where Autocrop will produce a bad crop is when, during the search process, it happens to choose an inside pixel that is the same colour as the background. This would cause the edges of the crop to be dragged inwards. The binary search method has the potential for the biggest error, and the single pixel the smallest with the slice method not far behind.
We're not certain how often this is likely to cause a problem as we haven't been using Autocrop ourselves for that long. We'd be very interested to hear your views.