this is an article i found on hubpages.com
i found it very useful. this software, which is called Prayaya V3, seems enables your to run any app and games off USB drive easily.
i think it will be very useful for you.
here is the article link:
[url]http://hubpages.com/hub/How-to-make-Plants-VS-Zombies-portable[/url]
[URL]http://hubpages.com/hub/make-any-app-portable-in-a-ipod-with-prayaya-V3[/URL]