Many of these features are ready to implement today.
We don’t have to wait for entire specs to be completed, we can start using some hawtness now.
Well, as long as it’s enough that it works in Chrome, Safari, Opera and Firefox. If it needs to work in Internet Explorer you will have to wait for Internet Explorer 9 to get some amount of support for these new cool HTML5 features. How long that wait will be is hard to say, IE 9 is currently available as a test drive with no planned release date for the final build.
It also seems like Internet Explorer 9 will not be supported for Windows XP. That means Internet Explorer 8 will be the last version to run on that platform.