During my tests i installed a Debian 6 Squeeze on an Old laptop with an integrated ethernet card and a PCMCIA wireless card.
Problem, after the install all works perfectly but the wireless, and installing new packages without a net is not so comfortable.
You have to search on the net for the name of the packages you need, download them and ALL their dependency put them on a USB stick and then hope that this work and resolve your problem. Naturally the first try (new kernel module for the wireless card, a rt61 + his firmware) did not solve the problem.
So I decided to use my laptop with Xubuntu as gateway, the Xubuntu has a working wireless card and a free ethernet slot.
So what I did is put a crossover-cable between them and configure the Xubuntu as a gateway, all worked fine and now the other laptop is updating the system.
This is how i did it in details.