I'm trying to get my Diecimila board communicating with my OS X system and don't seem to be having any luck.
I first tried just loading the usb driver that came with Arduino 0009, rebooting, plugging in the Diecimila and launching Arduino 009. Unfortunately, the usb serial driver wasn't listed under Tools -> Serial Port.
There is a slightly newer version of the drivers on the FTDI website: http://www.ftdichip.com/Drivers/VCP.htm. You might try uninstalling the ones that came with Arduino and installing those.
What version of OS X do you have? Intel or PPC Mac? In the System Profiler, when the board is connected do you see FT232RL USB UART under USB? If you open a Terminal and do:
As you can see, there's now a tty.usbserial entry under /dev/. This wasn't there last night when I was trying to get the communications working. I'm a bit confused.
But I did just upload the Blink example sketch and its running on the board now. Wahoo!