Think the cable they're referring to is a crossover ethernet cable. Of course, if you're always in different areas of the house and don't want to move the Powerbook, this isn't a great solution, unless you have some easy way of snaking cable through walls etc.
I would suggest getting a crossover cable though just so that you can use one machine to back up the other easily.
Of course, there's always the wireless solution, but that will cost considerably more. You can get a PCMCIA wireless ethernet card for your Pismo, buy a wireless router and set up a LAN. But we're talking well over $100 CDN (the wireless PCMCIA card being the expensive item these days).
If you're going to use CF cards, I'd suggest that you keep one card just for this purpose, rather than changing the format repeatedly, and having to remember to reformat depending on what you're doing.