Open the VMX file (e.g. Windows XP Professional.vmx)
Change the device type:
ide0:0.deviceType = "cdrom-image"
Change the filename (windows.iso can be copied from the VMWare Player directory):
ide0:0.filename = "windows.iso"
Comment the following line:
#ide0:0.autodetect = "TRUE"
After the Virtual Machine has booted, enable the CDROM drive and install VMWare Tools.
After installation, revert the VMX file back to the original state.