after you've implemented it, every time you try to open a folder using Windows Explorer, the Search Companion window opens instead of the folder you selected. The workaround is a quick Registry edit described in Knowledge Base article 321379, where this hack is found.
Rather than modify the context menu, I added a shortcut to the bat file to my send to folder:
a) lets me run it against both directories and individual files,
b) easier to remember where it is (both to modify and to share with others)
c) doesn't require the regedit hack from KB321379
caveat; WinXP-Pro SP1 with a lot of post SP2 updates, so...