In a secondary terminal (xterm, etc.) do:
Code:
sudo tail -f /var/log/messages
This should give you an indication of whether the device is connecting or not.
For example, this is the log message on my Fedoria 14 system:
Code:
Jan 9 10:10:21 wogglebug kernel: [1066586.000097] usb 3-2: new full speed USB device using uhci_hcd and address 19
Jan 9 10:10:22 wogglebug kernel: [1066586.153101] usb 3-2: New USB device found, idVendor=16c0, idProduct=0483
Jan 9 10:10:22 wogglebug kernel: [1066586.153106] usb 3-2: New USB device strings: Mfr=1, Product=2, SerialNumber=3
Jan 9 10:10:22 wogglebug kernel: [1066586.153132] usb 3-2: Product: USB Serial
Jan 9 10:10:22 wogglebug kernel: [1066586.153135] usb 3-2: Manufacturer: Teensyduino
Jan 9 10:10:22 wogglebug kernel: [1066586.153138] usb 3-2: SerialNumber: 12345
Jan 9 10:10:22 wogglebug kernel: [1066586.156769] cdc_acm 3-2:1.0: This device cannot do calls on its own. It is not a modem.
Jan 9 10:10:22 wogglebug kernel: [1066586.156863] cdc_acm 3-2:1.0: ttyACM0: USB ACM device
Jan 9 10:10:22 wogglebug mtp-probe: checking bus 3, device 19: "/sys/devices/pci0000:00/0000:00:1d.1/usb3/3-2"
Jan 9 10:10:22 wogglebug mtp-probe: bus: 3, device: 19 was not an MTP device
At this point, I run the Arduino program, and compile/upload my program:
Code:
Jan 9 10:10:23 wogglebug kernel: [1066587.955071] usb 3-2: USB disconnect, address 19
Jan 9 10:10:24 wogglebug kernel: [1066588.698328] usb 3-2: new full speed USB device using uhci_hcd and address 20
Jan 9 10:10:24 wogglebug kernel: [1066588.831113] usb 3-2: New USB device found, idVendor=16c0, idProduct=0478
Jan 9 10:10:24 wogglebug kernel: [1066588.831118] usb 3-2: New USB device strings: Mfr=0, Product=0, SerialNumber=0
Jan 9 10:10:24 wogglebug kernel: [1066588.837617] generic-usb 0003:16C0:0478.0009: hidraw1: USB HID v1.11 Device [HID 16c0:0478] on usb-0000:00:1d.1-2/input0
Jan 9 10:10:24 wogglebug mtp-probe: checking bus 3, device 20: "/sys/devices/pci0000:00/0000:00:1d.1/usb3/3-2"
Jan 9 10:10:24 wogglebug mtp-probe: bus: 3, device: 20 was not an MTP device
Jan 9 10:10:25 wogglebug kernel: [1066589.762330] usb 3-2: USB disconnect, address 20
Jan 9 10:10:25 wogglebug kernel: [1066589.969091] usb 3-2: new full speed USB device using uhci_hcd and address 21
Jan 9 10:10:26 wogglebug kernel: [1066590.126130] usb 3-2: New USB device found, idVendor=16c0, idProduct=0483
Jan 9 10:10:26 wogglebug kernel: [1066590.126157] usb 3-2: New USB device strings: Mfr=1, Product=2, SerialNumber=3
Jan 9 10:10:26 wogglebug kernel: [1066590.126162] usb 3-2: Product: USB Serial
Jan 9 10:10:26 wogglebug kernel: [1066590.126164] usb 3-2: Manufacturer: Teensyduino
Jan 9 10:10:26 wogglebug kernel: [1066590.126189] usb 3-2: SerialNumber: 12345
Jan 9 10:10:26 wogglebug kernel: [1066590.129363] cdc_acm 3-2:1.0: This device cannot do calls on its own. It is not a modem.
Jan 9 10:10:26 wogglebug kernel: [1066590.129483] cdc_acm 3-2:1.0: ttyACM0: USB ACM device
Jan 9 10:10:26 wogglebug mtp-probe: checking bus 3, device 21: "/sys/devices/pci0000:00/0000:00:1d.1/usb3/3-2"
Jan 9 10:10:26 wogglebug mtp-probe: bus: 3, device: 21 was not an MTP device
If you just loaded the udev rules, you may need to restart the udev process (simplest to reboot, there may be a Ubuntu specific command to restart it).

I should mention that it may your cable is wonky. I have a cable that has both micro and mini USB connections on it (which isn't covered by the USB spec), and at times it will not connect the device.