NooElec PL2303 USB to Serial (TTL) Module/Adapter with Female and Male Wiring Harnesses & Test Jumper. Compatible with Windows 98 through Windows 7; Mac OS 8 through OS X, Linux and Android!
A handy USB to TTL converter based on the PL2303.3 LEDs are on-board to indicate power, data reception and data transmission.   A 5V and 3.3V output is available--you can power your project directly from the USB port, so it functions as a USB power supply, too.  The 5-pin I/O is clearly labelled on the board.Both a 5-pin female to male and a 5-pin female to female multicolor jumper cable set are included!   This will allow connection to Arduino, breadboards and nearly any other board with standard male or female headers.A shunt is also included in order to connect TX and RX to conduct loopback testing.Excellent driver support--drivers are available for Windows 98 to Windows 7 (32 bit and 64 bit), Mac OS 8 to OS X (32 bit and 64 bit) and Linux.  Even Android is supported!