I already own an Arduino Diecimila, obviously with a USB interface, and was wondering if I could connect the TX and RX pins on that to say the TX and RX pins on a Bare Bones Board so that when I upload a sketch it is burnt onto both chips, eliminating the need for any extra serial or usb cables.
It should certainly bring down the cost for a second unit, requiring only the initial investment for a full Arduino.
you could quite easily connect both the rx pins together, but only connect one tx or they will fight each other when they reply.
If you do this, one will be programmed "blind" - ie your computer will get zero feedback as to whether or not it worked, because only one can send signals back at a time.
Also, you'll need to ensure that they both reset at the same time.
You may want to have a look for the threads about using the arduino to program other chips
Or program one chip and swap it into the second board.
Or build an ICSP programmer and use that option from the Arduino IDE to prgram boards without a USB port.
Thanks for the heads up, it has put me one step closer to realising £5 Arduinos :D.