If you're already experienced with VI3, there will be a 2-day "What's New" course for you to update your skills to vSphere 4 and learn how to migrate a VI3 environment to vSphere 4. You can actually take a pre-release of this class now, running on the Release Candidate software:
The current Install & Configure course for VI3 will be renamed to "Install, Configure, Manage" for vSphere 4. The course will remain at 4 days in length, and will still be the closest match to the VCP exam for vSphere.
There will also be a "Fast Track" course for vSphere 4, this will be 5 days with extended hours as at currently is for VI3. The content will be the new "Install, Configure, Manage" course, plus additional content on availability, scalability and troubleshooting.
VMware have yet to decide whether to release dedicated courses on availability, scalability and troubleshooting, along with possible content on automation and scripting, and possibly other topics too. These may only be available as part of the "Fast Track", as a separate 4-day course, or even as individual 1 or 2-day courses.
So, the important bit - when will they be available?
The pre-release "What's New" is available now.
The final release of "What's New" will be available from the end of June.
"Install, Configure, Manage" will also be available from the end of June.
"Fast Track" will be available from the end of July.
Keep checking back here, and on the main Global Knowledge site for further details:
UPDATE on 26th April:
VMware Education have now posted the official course overviews for "What's New" and "Install, Configure, Manage" on their website: