PGPdisk Substitute In OS X

Bill Lamb offers this suggestion for a PGPdisk substitute in Mac OS X, although its unclear the level of security available using this technique. He writes: "Users of PGP who are concerned that NAI will not release a version of the software for Mac OS X may be interested in a free workaround for the PGPdisk application, a part of the commercial PGP product not available with PGPfreeware. Disk Copy included with OS X will allow users to create disk images of< various sizes and encrypt the contents with AES (Advanced Encryption Standard) at 128 bits. The use of these images is functionally similar to PGPdisk containers under Classic Mac OS. Passphrases can optionally be saved to the keychain."