that's a good guide, however i wouldn't necessarily recommend it for running flash.
the main issue i see, is mounting your home directory inside the chroot, running the browser as the same user.
thereby allowing access to your files, if there is a severe exploit in flash.
further, the commands use debian sid/unstable, whereas packages in testing are more likely to get patches quicker.
craigevil wrote:get rid of all of the sudo references, it is not setup by default on Debian.
just did a major rewrite. sudo is only used to launch or update the chroot browser, without asking for a password.