All you need to do is to place this in your <head> section :
<style type="text/css">
img { behavior: url(
http://www.domain.com/whatever/css/iepngfix.htc) }
</style>
and have that iepngfix.htc in place
That should do the trick.
I can't check that on my laptop. I don't have IE5 or 6 or 7
Note to anybody with older IE version:
http://www.twinhelix.com/css/iepngfix/demo/
Is demo image on right side transparent ?