If you'd like to download the tiny serial VT100 emulator for any Mac, click here. Set it to connect via Serial Console port COM1 (or whichever COM your serial cable is on, COM1 will almost always be it. In order to make it useable, I wrote a small VT100 emulator for it, and set it up in my girlfriend's dorm room as a terminal. Once you've got TeraTerm up and running and your cable connected, you're going to have to check the settings in TeraTerm.
#VT100 TERMINAL EMULATOR MAC MAC OS X#
You need to get a null modem serial cable (available pretty much anywhere for pretty cheap,) and connect another computer (linux, Mac OS X, FreeBSD or Microsoft Windows,) and connect it to your server with the serial cable (serial-to-serial there are usb-to-serial cables around if your "working" computer doesn't have a serial connection.) Once you've done that, use a terminal application that supports the VT100 terminal emulation - on MS Windows, I prefer TeraTerm, but you can use Windows' built-in HyperTerm from Mac OS X you can use the ZTerm application.
It supports language encodings, VT100/ANSI/XTERM emulation and many. For starters, you can't use a Sun keyboard, so you must install via serial console. iTerm is a full featured terminal emulation program written for OS X using Cocoa. FreeBSD installation on a Sparc machine can be a frustrating thing for the beginner.