VMware vSphere 4 was released sometimes ago and the new version of VMware vSphere are coming soon. According to VMware vSphere Blog, they are looking for beta tester as below:

Want to be a vSphere beta participant?
We are looking for beta participants to test out some new vSphere features currently in development. Interested? If so, contact your VMware account team for further details.

What are you waiting for? Contact your local VMware Account Team now!

Good luck!