yep, that's it.
Writing this connected via PAN to my N900 which does GPRS (well
in the train even this is luck).
The vmware-image with scratchbox is really cool.

Added a udev-rule which whenever a bnep[0-9]* comes up
starts an instance of my userspace-nat daemon and kills
it again when the bnep-device disappears.
I think I'm gonna stay with bluetooth connection for now.
It is simple, costs comparably little CPU-Power and when
doing a terminal session to my N900 it is much less choppy
as when I do that when Laptop and N900 see each other
via a WLAN-Access-Point at home.
And what might be interesting in addition PAN leaves
WLAN unused to e.g. connect to a public WLAN-Hotspot
and share this connection.
One drawback I see at the moment is that 2 PAN clients
connected to my N900 don't see each other at the moment
as they are living each in their private userspace network-stack.
Does anybody know if it is easily possible to get the linux-bridge
to work with stock kernel N900?
Other solution would be to have on the fly interface-adding/removal
to a single instance of the userspace-nat-daemon.
By the way I can even switch back an forth between WLAN-Hotspot
and UMTS as I'm just doing while writing this text.

How to get IP address?

I need to implement the scheme: internet wifi NAP> N800 (Easy Debian)> usbnet> PC (Ubuntu)
It may be an option Bluetooth PAN, but there is less difference in the speed of usb.

I combined the instructions:
http://wiki.maemo.org/USB_networking (the role of the host performs the N800)
http://talk.maemo.org/showpost.php?p...4&postcount=25 (wlan0 changed to usb0)


My actions:

(/etc/network/interfaces is empty, not usb0, bnep0)

1. N800:
/etc/init.d/usbnet start
/etc/init.d/usbnet start
/etc/init.d/usbnet stop
/etc/init.d/usbnet start

2. PC: modprobe usbnet
(подсоединяю кабель)
3. N800: ifconfig usb0 10.0.0.1 up
4. PC: ifconfig usb0 10.0.0.2 up
root@usxakov:/home/temp.info/n800/man# ping 10.0.0.1
PING 10.0.0.1 (10.0.0.1) 56(84) bytes of data.
64 bytes from 10.0.0.1: icmp_req=1 ttl=64 time=3.09 ms
64 bytes from 10.0.0.1: icmp_req=2 ttl=64 time=0.491 ms
64 bytes from 10.0.0.1: icmp_req=3 ttl=64 time=0.491 ms
^C
--- 10.0.0.1 ping statistics ---
3 packets transmitted, 3 received, 0% packet loss, time 2000ms
rtt min/avg/max/mdev = 0.491/1.357/3.091/1.226 ms

5. N800:
vde_switch -s /var/run/vde_sock -d
slirpvde -s /var/run/vde_sock -D -d
vde_pcapplug -s /var/run/vde_sock usb0 -d

6. PC:
root@usxakov:/etc/network# dhclient -d -s 10.0.0.1
Internet Systems Consortium DHCP Client 4.1-ESV-R4
Copyright 2004-2011 Internet Systems Consortium.
All rights reserved.
For info, please visit https://www.isc.org/software/dhcp/

Listening on LPF/usb0/72:2c:ae:5a:c8:76
Sending on LPF/usb0/72:2c:ae:5a:c8:76
Sending on Socket/fallback
DHCPDISCOVER on usb0 to 10.0.0.1 port 67 interval 3
DHCPDISCOVER on usb0 to 10.0.0.1 port 67 interval 8
DHCPDISCOVER on usb0 to 10.0.0.1 port 67 interval 7
DHCPDISCOVER on usb0 to 10.0.0.1 port 67 interval 9
DHCPDISCOVER on usb0 to 10.0.0.1 port 67 interval 12
DHCPDISCOVER on usb0 to 10.0.0.1 port 67 interval 13
DHCPDISCOVER on usb0 to 10.0.0.1 port 67 interval 15
DHCPDISCOVER on usb0 to 10.0.0.1 port 67 interval 20
DHCPDISCOVER on usb0 to 10.0.0.1 port 67 interval 20
DHCPDISCOVER on usb0 to 10.0.0.1 port 67 interval 17
DHCPDISCOVER on usb0 to 10.0.0.1 port 67 interval 18
DHCPDISCOVER on usb0 to 10.0.0.1 port 67 interval 11
DHCPDISCOVER on usb0 to 10.0.0.1 port 67 interval 11
DHCPDISCOVER on usb0 to 10.0.0.1 port 67 interval 11
DHCPDISCOVER on usb0 to 10.0.0.1 port 67 interval 15
DHCPDISCOVER on usb0 to 10.0.0.1 port 67 interval 11
DHCPDISCOVER on usb0 to 10.0.0.1 port 67 interval 16
DHCPDISCOVER on usb0 to 10.0.0.1 port 67 interval 15
DHCPDISCOVER on usb0 to 10.0.0.1 port 67 interval 13
DHCPDISCOVER on usb0 to 10.0.0.1 port 67 interval 11
DHCPDISCOVER on usb0 to 10.0.0.1 port 67 interval 15
DHCPDISCOVER on usb0 to 10.0.0.1 port 67 interval 10
DHCPDISCOVER on usb0 to 10.0.0.1 port 67 interval 18
No DHCPOFFERS received.
No working leases in persistent database - sleeping.

P.S.
debian-n8x0-v3c.img.ext2 - works well, but does not support vde_pcapplug (vde 2.2.3)
debian-squeeze-img.tar.bz2 - browsers do not work
ubuntu-mer-java-img-v2.tar.bz2 - no image connected