
John Resig post an article about two new feaatures in WebKit CSS animation and CSS transition. Here's small excerpt from this article:
Apple, and the WebKit team, have recently proposed two different additions to CSS: CSS Transitions and CSS Animations.
The two specifications are confusingly named - and it's hard to tell what the difference is between them at first glance. However, to put it simply: CSS Transitions are easy to use, while CSS Animations are made for programmers.
Source:John Resig's blog.