FTDI 245R Relay board
Relay Board is driven by a ULN2803 with FTDI FT245R USB to parallel FIFO chip. This is an eight or four channel, USB controlled board with DC power supply. The normally open, normally closed and common pins are all available on the screw terminals. Each relay has LED to indicate whether it is in a powered state or not. Additional two led will flash on USB transactions - for reception data and for the transmission of data to the PC. Led near by power supply connector indicate presence of 12V DC.
Here is the links for projects based on FT245R relay board: