The SCUMM engine (aka Spu(TM) or SPUTM) is a VM, and the game is fully scripted using the SCUMM language. You cannot use runtimes not officially supported by Apple in iPhone apps.

There is an iPhone port of ScummVM, but you'll need to jailbreak your phone, and to get the original data files.

http://www.scummvm.org

But the touchscreen interface isn't that good, because your fingers actually hide the cursor and the bottom part of the screen where contextual info is displayed.

Edit: psadauskas beat me to it.

If you've jailbroken your phone, you can: http://wiki.scummvm.org/index.php/IPhone

Thanks! I can't wait to load Day of the Tentacle onto my iPod Touch!