You can use a free tool called "VMware Converter", available here: http://www.vmware.com/products/converter/
VMware Converter is a Windows app. I haven't used it for P2V, but it does work great. (used for converting between ESX and VMware Server)
Problem is that the OP wants to P2V a CentOS system. The VMware Converter FAQ states" NOTE: Experimental support only is available for Linux-based physical to virtual machine conversions using the Vmware Converter BootCD (cold cloning) if the source physical machine has SCSI disks.
...so YMMV.
http://www.vmware.com/products/converter/faqs.html
-Shawn