In this (very simple and _small_) PCB you can find a plug for a JeeNode-v5 (more info on http://cafe.jeelabs.net/lab/jn5) with a DS18B20 temperature sensor

[from http://cafe.jeelabs.net/lab/jn4]

The JeeNode is based on an Atmel ATmega328 - 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.

It includes a radio (!) HopeRF wireless module, which is available for the 433, 868, or 915 MHz frequency bands. The RFM12B has its own very lightweight RF12 driver library.

This project adds a temperature sensor (DS18B20) to a JeeNode-v5;