The driver can be found at:    
http://people.freebsd.org/~wpaul/RealTek/

Here are instructions on how to add the driver to an
existing FreeBSD system:

- Download the version of if_rl.c and if_rlreg.h that goes with your
  version of FreeBSD. The 3.0 directory contains code for FreeBSD 3.0.
  The 2.2 directory is for FreeBSD 2.2.5, 2.2.6 and 2.2.7.

- Make sure you have the kernel source unpacked under /usr/src.  

- Copy if_rl.c and if_rlreg.h to /sys/pci.

- Edit /sys/conf/files and add a line that says: 

pci/if_rl.c             optional rl device-driver

- Edit your kernel config file (e.g. /sys/i386/conf/GENERIC) and add
  a line that says: 

device  rl0

- config and compile a new kernel

- copy the kernel to the root directory, then reboot.

Interfaces should be detected as rl0, rl1, etc... You should edit 
/etc/rc.conf to have the interface brought up automatically when the
system boots.
