This is most likely a SQL issue or SQL configuration issue. There are countless SQL issues and mis-configurations that can cause 100% CPU use. Poorly written code, reports, or queries can all do this. I belive you need to start by investigating what is generating all of the activity.
On the VMware side, I'd suggest starting with this link (without knowing more about the situation);
http://kb.vmware.com/kb/2034127
Here are some useful links to help track down specifically what is causing the abuse;
1) How to find out how much CPU a SQL Server process is really using
2) sql server - CPU utilization by database? - Stack Overflow
And here is a great paper from Microsoft for SWL 2008 on using Resource Governor to control performance;
http://download.microsoft.com/download/D/B/D/DBDE7972-1EB9-470A-BA18-58849DB3EB3B/ResourceGov.docx
Without some research identifying exactly what is causing the load, I think it's premature to point at vSphere as a culprit.