Because I erroneously thought this was one of the new fields, I didn't think there would be a script on Doug's Scripts. However there are a couple of important differences between my script and the script on www.dougscripts.com.

1. The dougscripts version requires you to select all of the tracks you want to update, whereas mine grabs all of the tracks which don't already have an Album Artist listed.
2. My version checks all of the tracks in an album to see if they all have the same artist, and if they do, it uses that artist for the Album Artist, but if the artists are different for any of the tracks, my script puts up a dialog box with all of the found artists names plus "Various Artists" and "None of the above". Choosing "None of the above" will leave the Album Artist blank and put the tracks in the second playlist for easy manual editing.

And rolling my own was pretty quick and easy until I started revising and testing to publish here.