This article starts off with: “portable applications are packaged so you can carry around on any portable device, USB thumb drive, iPod, portable hard drive, memory card, other portable device (or also on your internal hard disk), taking your preferences with you.”
The article itself is kind of old. (November 2007) However most the applications listed are still available even though updates are now available for those. Also they are all free.
Portable applications for OS X included are:
Firefox (browser),Thunderbird (email), Adium (chat for most networks), AbiWord (similar to Microsoft® Word), Nvu (HTML wysiwyg editor), Sunbird (calendar and task Manager), Cyberduck (FTP and SFTP Browser), Check Off (To-Do Manager), Gimp.app
(GNU Image Manipulation Program), Newspeak (IRC client), OpenOffice.org (Office suite) and more. Also many applications are have cross platform versions.
See the full list complete with download links at: here.
