Gods it's been a while since I was here! Anyway, just a note on using _parent instead of _top:
_parent will work grand for what you need, but you'll find that if you're using nested framesets, i.e. a frameset within a frameset, that that will target the top of the *current* frameset, not the top of the window. So _top is what you should *really* be using in these circumstances.
But if it works it works!
Cheers,
adam