Apple’s effect looks like this:

This effect only works in Webkit-based browsers like Safari and Chrome at this time and requires Sass 3 and the most recent version of Compass:
h1 {
@include linear-gradient(color-stops(#999, black));
-webkit-background-clip: text;
-webkit-text-fill-color: transparent;
}
Or, if you prefer plain CSS:
h1 { background-image: -webkit-gradient(linear, 0% 0%, 0% 100%, color-stop(0%, #999999), color-stop(100%, #000000)); -webkit-background-clip: text; -webkit-text-fill-color: transparent; }
Which renders as:

Comments?
Let me know at thomas@awardwinningfjords.com and I'll amend the article as necessary.