I am attempting to play with the wifly shield. I have some code which I have loaded to the arduino, but now I have to communicate with it via "terminal" - this is a windows example. How do I do this in linux? (ubuntu)
Doesn't the serial monitor in the Arduino IDE work for you?
Or do you want to communicate through the terminal, if so search for Linux tty.
I use bash scripting
stty -F /dev/ttyUSB0 cs8 115200 ignbrk -brkint -icrnl -imaxbel -opost -onlcr -isig -icanon -iexten -echo -echoe -echok -echoctl -echoke noflsh -ixon -crtscts -clocal
cat /dev/ttyUSB0|head -n 6|tail -n 3 >> /root/arduino #
The above sets ttyUSB0 to 115200 baud and reads the last 3 lines of 6 lines read into a file 'arduino' in roots home folder.
I have the arduino sending data out in space delimited lines of text in groups of 3 lines continuously. It reads 6 and takes the last 3 in case it joins the conversation part way through and corrupts the first line.
I send single character commands back to the arduino
echo 'Z' > /dev/ttyUSB0
If it resets the arduino each time (it may or may not depending on your computer) stick something like a 1 - 10uF capacitor across gnd and the reset pin to 'swallow' the DTR auto reset pulse.
I have it all running through cron every minute to produce :
something like,
screen /dev/ttyUSB0 9600
should work, may have it the wrong way round, and I can't remember the default escape character to close the connection...
Or, use cutecom if you want a gui 
After the mentioned stty lines, I've been using the following:
tail -f /dev/ttyUSB0
That way the AVR doesn't reset with every "cat" line.
To get serial data in, I just use
echo -n "something" > /dev/ttyUSB0
...or leave off the "-n" if a carriage return is needed.