You should add this to your lineup of PortableApps https://www.torproject.org/
Tor protects you by bouncing your communications around a distributed network of relays run by volunteers all around the world: it prevents somebody watching your Internet connection from learning what sites you visit, and it prevents the sites you visit from learning your physical location. Tor works with many of your existing applications, including web browsers, instant messaging clients, remote login, and other applications based on the TCP protocol.
Already bundled to run on a USB flash drive, comes with a pre-configured web browser to protect your anonymity, and is self-contained.
For this public service announcement. As is stated, it's "already bundled to run on a USB flash drive.".
IF you want it in PAL format, go to any app I have released a Dev Test for, and click the SkyDrive link.
I have an unreleased Tor/Vidalia and Tor Browser there. Both come from the Tor Browser Bundle, I just separated them as TBB - TB = Portable Vidalia Bundle, for those who'd want to run it on their system and manually configure things, without installing it.
I have quite a few apps there I haven't posted to PAL Dev Test site, due to lack of interest or frequency of updates. Not like anyone has really helped find bugs with it, short of VBA-M to some degree. I couldn't be bothered to maintain 20+ posts with MD5 and version numbers if nobody is viewing them.