Linux 2.6 kernels and VMWare clock drift issues
The 2.6 kernel changed the way the clock is configured. This can cause massive clock drift in a matter of minutes for any guest running a 2.6 kernel like Trustix 3.0 and CentOS/RHEL 4.x
Links to various VMWare time related documents:
VMware Time Sync and Windows Time Service
Time Keeping In VMWare virtual Machines
Clock in a Linux Guest Runs More Slowly or Quickly Than Real Time