If you want attribute selector in IE6, you can use Dean Edward IE.js.
http://dean.edwards.name/IE7/
That will make IE 5+ behave much more like IE7
supports the following CSS selectors:
parent > child
adjacent + sibling
adjacent ~ sibling
[attr], [attr="value"], [attr~="value"] etc
.multiple.classes (fixes bug)
:hover, :active, :focus (for all elements)
:first-child, :last-child, only-child, nth-child, nth-last-child
:checked, :disabled, :enabled
:empty, :contains(), :not()
:before/:after/content:
:lang()
I didn't have IE6 (use IE7) so i can't said it worked, but give it a try