Recently switched from Windows to Ubuntu 10.04 LTS (disclaimer: absolute linux newb). I have two Duemilanoves. One I can upload sketches and use serial monitor, no problems. The other I get an error:
avrdude: stk500_recv(): programmer is not responding
and cannot use serial monitor (however loop back test works). If I use $lsusb when each board is plugged in, one at a time, the terminal shows
Bus 004 Device 002: ID 0403:6001 Future Technology Devices International, Ltd FT232 USB- Serial (UART) IC
with, of course different device numbers. Each board uses (is assigned to) the same port every time: /dev/ttyUSB0. In Windows each was assigned a different com port, as I don't know linux, I don't know if that is important.