For our class project we are going to use HyperTerminal to communicate to something we are building that is attached to our laptops using USB. We're supposed to use HyperTerminal.
http://technet.microsoft.com/en-us/library/cc736511%28WS.10%29.aspx
I can't believe that a program that does the same thing doesn't exist in Linux. What programs that can do the same thing are available in Linux and Mac OSX?
Unix systems might not have an exact equivalent because HyperTerminal does two unrelated jobs which in unix are done by separate programs.
One job is providing a text terminal inside a GUI environment. This job is done by terminal emulators such as gnome-terminal, konsole, rxvt, Terminal.app, xterm, ...
Another job is converting between user interactions and serial port interactions (since you use HyperTerminal to connect to it under Windows, I presume the device uses the serial-over-USB protocol). Under Linux, minicom is often used for this; there are undoubtedly alternatives. Whatever program you choose needs to be connected to /dev/ttyUSB0 (or /dev/ttyUSB1, etc, if you have more than one device).
Try out screen. It's very portable, comes installed by default on Mac OS X and Ubuntu, and can do a lot of wizardy things in addition to connecting your usual terminal emulator (xterm / Terminal.app / etc) to a serial console. Here's a tutorial.
This may help. It's one of the first things that came up when googling "USB serial client". Note that you'll need to connect to a serial device (not necessarily the one listed on that link) using a terminal client in the *nix variants. In most flavors of *nix the device will be found in /dev/ after attaching the USB cable. A quick way to find out which device is to do this:
find /dev -ls > before.txt
(attach your device)
find /dev -ls > after.txt
diff before.txt after.txt
Minicom is a very nice serial communication program for Linux, over the years I've used it with all kinds of bizarre hardware requiring RS-232 communication. For USB devices the device you'll need to use will be something like /dev/ttyUSB0.
In OS X you have Terminal.app and in Linux you have several choices including xterm and gnome-terminal. I would recommend PuTTY for Windows over HyperTerminal.