There are a number of threads on that subject (one I started myself : http://www.donationc...ex.php?topic=10469.0
, and other ones like : http://www.donationc...dex.php?topic=7469.0
Usually, the consensus is that there are no great and infallible (portable, robust, etc.) ways of tagging on windows XP, and the summary tab found in the file's property can unfortunately be pretty unreliable (not accessible under certain circumstances) and not that convenient to use -- edit, modify, search with a desktop search program, etc.
As for software, there's tag2find (the best tagging software I found) but it might disappear or go open source soon... There may are other solutions too, but I stopped searching once I decided to adopt a solution... after much thinking and pondering I now use a system which integrates tags in filenames
. Yup, pretty straightforward, if you're careful with path length. I use AutoHotkey to implement that (but any software to systematize your file names would do; ie : direct access, intellicomplete).