[ILUG] minimal requirements for a Wireshark-only router netbook?

[Brendan Kehoe]

We're in Maine for a trip and are using a satellite-based Internet
connection to be online.  It's got a nasty bandwidth cap in place.  I'm
looking to use a netbook running distro-du-jour to run Wineshark to be
able to catch sudden traffic bleeding.

Right now I've got a laptop running Vista set up between the HughesNet
HN7000S satellite modem and our Linksys WRT54G wireless router for
actually using it.  On the laptop and its two interfaces (one being the
regular Ethernet port, the other a Linksys/Cisco USB300M adapter) I've
got Wireshark running with name resolution enabled so I can see in a
glance what the highest traffic is at the moment.  I'm finding
high-bandwidth things (AVGFree updates, Mozilla updates, or even a
family member's Mac doing an OS X update) and can then tweak the
computer/laptop to disable those things.  It also works when our nephew
was with us and his Mac had "Top Sites" enabled in Safari, which gets
the full contents of 12 pages simultaneously.

Anyway, I'm looking to take back the Vista laptop (needed for work) and
replace it with a netbook which would have enough energy to do the job. 
Have any of you used something like this as a router or anything which
processes network traffic?  Are there limitations to any particular
processors which ship in these?  (Atom, Celeron, etc?)

Thanks for any suggestions,
B