As we all know Pleo has a USB port. I have some utilities that let me see what is going on with USB. Here is a dump of Pleo's "Device Descriptor".

Device Descriptor:
bcdUSB:             0x0200
bDeviceClass:         0x02
bDeviceSubClass:      0x00
bDeviceProtocol:      0x00
bMaxPacketSize0:      0x08 (8)
idVendor:           0x6962
idProduct:          0x0100
bcdDevice:          0x0100
iManufacturer:        0x01
iProduct:             0x02
iSerialNumber:        0x03
bNumConfigurations:   0x01
ConnectionStatus: DeviceConnected
Current Config Value: 0x00
Device Bus Speed:     Full
Device Address:       0x02
Open Pipes:              0

So Pleo is a USB 2.0 device.
The Vendor id is "6962" and resolves to "Ugobe Life Forms, Inc."
The Device Protocol is "0" and is "Control/Bulk/Interrupt (CBI)"

I tried some standard USB to Serial drivers just on a whim and no luck.
So until Uglobe has drivers for download this is all we got.