Hey, just wanted to add my two cents.
This is a serious problem, not one that can be solved through GUI methods. Not as simple as checking/unchecking a box, unfortunately. So don't make any more suggestions like that.
There are a number of different methods that ARE supposed to work, but DON'T. These include the solutions using the chflags command line utility, and EVEN the SetFile utility doesn't work if you've installed OS X Developer Tools!! (SetFile gives me a -5000 error code which is a generic "accessDenied" error for Mac OS)
However, if you want to try them on your own machine, here are the commands that SHOULD have worked:
"sudo chflags nouchg <name of file>"
"sudo /Developer/Tools/SetFile -a l <name of file>"
There ARE 3rd-party apps designed specifically to handle this heinous "feature," but if the above two commands don't work, I doubt any other program is going to help. But you're welcome to try.
I think it may be easier to do this from a Windows machine (my drive is FAT32), but I haven't tried.