The still-in-Alpha IE7 (not to be confused with the still-in-Beta Microsoft Browser) Compliance Patch is simply:
…an attempt to make Microsoft Internet Explorer more compliant when it comes to web standards.
IE7 loads and parses all style sheets into a form that Explorer can understand. You can then use most CSS2/CSS3 selectors without having to resort to CSS hacks
The lightweight script is a single-line inclusion in your HTML/XML document. No alteration of your original markup is necessary. Neither do you have to alter your CSS (more)
In sum, it should fix all those little bugs in IE6. For the times you just can’t use the Fox.