vmware howto availability

[jimf]

Hi list,
was wondering if anyone could point me in the direction of an installation howto for vmware. tried to install it from the ports but encountered problems with the following output

# make install
===>  Building for vmware-1.1.2.364
===> vmmon-only
"/usr/share/mk/bsd.kmod.mk", line 10: "can't find kernel source tree"
*** Error code 1

Stop in /usr/ports/emulators/vmware/work/vmware-distrib.
*** Error code 1

Stop in /usr/ports/emulators/vmware.
*** Error code 1

Stop in /usr/ports/emulators/vmware.
*** Error code 1

Stop in /usr/ports/emulators/vmware.
*** Error code 1

Stop in /usr/ports/emulators/vmware.

#

TIA

jimf