Awesome, and you can string them together using I2C (two wire interface) and the Wire.h library (no hacks or mods required)
Pull ups are 1.8k.
The software I tested from the Arduino 10 examples, used:-
Output from the slave to the serial monitor, will look like this:-
x is 0
x is 1
x is 2
x is 255
x is 0
In the picture, the "Slave" is the lilypad connected to the USB adaptor.
So, aside from being cute and inexpensive, the lilypads are a nice solution for adding an extra hardware serial port if there is ever the need.
A serial device can be connected to the hardware serial pins on the "Master" lilypad, and hardware "serial.available" can be used to retrieve data from the buffer, and then send it on to the "Slave" via TWI.
When the "Master" sends data to the "Slave", a receiveEvent is executed, breaking out of a loop. Data can then be read using Wire.available, and then resume a loop. With software serial, a loop can't resume until data is received, so if the device being read doesn't send any, a program hangs until it does.
If I understand the literature correctly, a considerable number of Lilypads can be connected this way. I'm not sure if that has any application in the wearable arts market, but I can think of a few useful things to do with it
PS: the polarity of the bottom bread board is different to the top, follow the wires and ignore the coloring of the breadboard