USB ELM323

Free software:
Scantool.net
GM Mode 22 Scan Tool by Terry
OBD Gauge for PalmOS and Pocket PC by Dana Peters
OBD Logger by Jonathan Senkerik
OBD-II ScanMaster by Wladimir Gurskij (ScanMaster 3.52 - local copy)
obd2crazy.com
OBD2 Scantool by Ivan Andrewjeski
OBDII for ELM322 by David Huffman
pyOBD by Donour Sizemore for MacOSX and Linux
RDDTC by Pete Calinski
Real Scan by Brent Harris
ScanTest for Pocket PC by Ivan Ganev aka a-ser
wOBD by WDT

Features:
Heavy & robust casing for rough service use
Connects to PC via USB
Working for ISO9141/KWP2000 protocol over ELM323 Interpreter MCU
Cable is based on certified ISO9141 Bus Transceivers and USB level shifters
Bi-colour led for each K-line which shows the current logic status
Powered from car battery over OBD2 connector .
Functions
Software for ELM32X-based interfaces:

USB ELM323

USB ELM323