iPod splits album into many

The Album Artists field should have Various Artists typed into it. *

Look at the following screenshots for a better idea of how this works. The screenshots show the information for all the songs on an album. That is, I have selected the complete album, even if it means grouping them in the Songs view:

For a single artist album, the Album Artist field can be blank or show the artist's name and the compilation box should be off, even if the album is Dire Straits Greatest Hits (i.e. a collection album):

For a single artist album with guest musicians on some songs, enter the main artist name in to the Album Artist field and again, the compilation box should be off:

For a proper Compilation album, that is, a collection of songs each by a different artist, the fields should look like the one below. This would appear to include the Spamalot album that you specifically mention. This time, it is important to have compilation turned on:

If you change this in your iTunes Library, you need to Sync your iPod with iTunes for those changes to be effective on the iPod. If you use Manually Manage for your iPod, you need to manually remove the album from the iPod and then put on the replacement version that you have changed.

* sentence edited by author after initial posting, for clarity.

I had the same issue and I discovered much to my surprise it was (in my case) a self inflicted problem involving the compilations option. Kudos to the fiend for the suggestion.