Thanks folks. I just did this with only extras-testing enabled, so it may be wise to removed the advice to enable -devel from the wiki page?

BTW, I previously found usb0: would not work at the same time as a usb or bluetooth PPP connection (/dev/ttyACM0 or rfcomm0) through the N900. Anyone know why?
That would have been better, as the PC gets a public internet address instead of NAT, while still being connected to the n900.