QTTabBar is a program that I beleive brings windows explorer up to date with the tabbed browsing we are familiar with while using Firefox or Internet Explorer.
QTTabBar works with both XP and Vista. It helps users who use a lot of windows while working, by organizing them into tabs. The program has a number of options to change the look and feel of the tabs.
It also allows you to have preview window that can show a preview of images. You open subfolders and view files in them without opening the actual folders.
There are a number of plugins to improve the functionality of this program, including folder lock, password protection, keeping a folder ‘always on top’, copying path, etc.