Tools needed
WinSCP or equivalent.
Putty or equivalent.
Ports that are going to be installed:
ESXi SSH Support
Your ESXi installation must have ssh enabled. (Google it)
Does ESXi support freeBSD?
Unfortunately, FreeBSD isn't officially supported on ESXi. But there is a way to install the tools provided by ESXi. They are just hidden. 
I. Tunnel into your ESXi Server with SCP
Once you are inside your ESXi server via SCP:
Head over to:
/usr/local/lib/vmware/isoimages
If you check the directory, you should see a freebsd.iso. Download that file to your desktop.
Next, extract it using winrar or whatever iso extracting software you prefer.
You should then see a file called VMWARE_F.TGZ, move it to your desktop.
Delete the freebsd.iso
II. Tunnel into your FreeBSD install with SCP
Once in, copy over that VMWARE_F.TGZ file to the vm.
Close the scp connection.
III. Connect with Putty via SSH
Now we're going to move that file to /tmp
mv VMWARE_F.TGZ /tmp
Extract the file
tar -xvf VMWARE_F.TGZ
move into vmware-tools-distrib
cd /tmp/vmware-tools-distrib
Note: Before attempting to install, please make sure you have Perl installed and updated.
To check simply type:
perl -v
If you get
perl: Command not found.
It needs to be installed, Install it by typing
pkg_add -r perl
While still in vmware-tools-distrib, CHMOD the following files to make them executable.
chmod +x vmware-install.pl bin/vmware-config-tools.pl bin/vmware-uninstall-tools.pl
IV. Tools Installation
Run the installation:
./vmware-install.pl (while in the vmware-tools-distrib directory)
Just go through the setup hitting ENTER (the default answers are fine).
You would get to the part where it will ask you if you want to invoke the command: "/usr/local/bin/vmware-config-tools.pl"
Set the answer to yes and hit enter.
Immediately after that you should see some shared object errors.

DONT PANIC! :smileysilly:
Install the compat6x port. It seems the vmware tools are for the 6.X version of FreeBSD, not native 8.
After that completes, create the following symbolic link (This is where VMware searches for the library):
ln -s /usr/local/lib/compat/libc.so.6 /lib
Finally, we rerun vmware-config-tools.pl
/usr/local/bin/vmware-config-tools.pl
If all went well, you should get a prompt telling you that the program is running in a remote session.
Just type yes and hit enter. (You will not get disconnected. I did this through putty). If you do then just rerun the config through the vmware infrastructure client console.
Congrats! You should see the daemon start up and show that the tools were installed successfully.
Note: These tools are directly from the ESXi Server. I checked with a windows 2003 install in which I did a legit tools install and compared the versions. (both matched version 3.5.0 build 153875).
Shutdown Issues
For those having issues with the vm not powering off completely after issueing the shutdown guest command.

Edit the following file
/usr/local/etc/rc.d/vmware-tools.sh
Locate vmware_start_guestd() and add the following to the function
--halt-command "/sbin/shutdown -p now"
Should look like this

Save and reboot
The VM should now power off instead of just sitting at the halted screen. 
MAKE SNAPSHOTS...If you feel something will break..save yourself the headache. That's what they're there for. :smileygrin:
-late
Sources: