The JeeNode is based on an Atmel ATmega 328 - the same as an Arduino - and was inspired by Modern Device's Really Bare Bones Board, which is like a minimal implementation of an Arduino. The USB communication interface has been removed and any USB-to-TTLSerial based on the FTDI232R chip is guaranteed to work as connection. Being compatible with Arduino boards such as the Duemilanove means that you can use the IDE to upload a sketch using any PC running Windows, Mac OS X, or Linux.
[Source] JeeNode (v4)