OK it looks like the Linksys WRT54G Wireless-G does support both parental controls and internet usage logging.

It is one of those more sophisticated hybrid devices that I mentioned.

If you connect through it the traffic will show up, and connecting to a proxy would be a dead giveaway.

As already suggested the only solution would be to connect directly to the modem, which might not be practical depending on its location in the house?

Also if anyone else in the house tried to connect to the internet whilst you were doing this the cat would be out of the bag!

I don't know if this is possible but you would need a pay-as-you-go mobile internet account and a dongle. A rather expensive solution I know, but all that I can think of that would not risk discovery on the home network, as you wouldn't be using it.

An ordinary account would be no good unless you could get the statements sent somewhere other than home college perhaps? Otherwise it would again be a dead giveaway.

All you would have to do then is boot from a live CD to protect you from any software installed on the laptop.