1. I edited /boot/loader.conf and added the following:
2. I edited the wallpaper found at http://www.freebsd.org/logo/wall3.jpg to make it 256 colors and 1024x768. You may download the modified version here.
3. I moved the wallpaper to /boot/kernel/splash.bmp
5. Enjoyed the splash screen. The only issue was that it didn't go away when the boot was finished until I pressed a key. This isn't an issue for me personally, since I use XDM, which cleared it away.