For projects like that I usually increase the page width in Document Setup and add a manual trim mark on the master page, but if you prefer, you can split the spreads. See InDesignSecrets » Blog Archive » Breaking Pages Apart to Bleed Off a Spine
See the comments on that page
Actually, I just noticed that Harbs of In-Tools has a free script called Separate Pages on his website here:
He even has a link to this discussion there. I tried the script on a 60-page document and it worked great – took 2 seconds!