A suggestion put forth on the Club Obi-Wan forums at indygear.com recommends stitching one side of the tongue to one side of the boot. I'm not explaining this clearly at all, am I? Head to indygear.com and search the forums for "tongue" and I think you'll find it.
I've experienced the problem myself, but am not crafty enough, nor have I pestered my wife to fix it for me, I just put up with it.