I agree HPNA 2.0 is the way to go. Do not get ANY HPNA 1.0 products, 2.0 is far more advanced for not much more $$$.
It took me a while to set up my home phone line network. Technically, you don't need any routers or anything. A lot of these HPNA cards have incompatibilites with WinXP and Win2000. I learned this after many trial and error with various cards, since there is only 1 HPNA 2.0 chipset out there, and all the cards are based on it. When it works, though, it works great.
What I did was take 2 10/100 PIC NIC cards and put them in PC#1. To one, I connected my cable modem. To the other, I connected a HPRO200 linksys router, but I am just using it as a ETHERNET/HOMEPNA bridge. It was actually cheaper then the bridge, go figure. In this setup it doesn't use ANY of the router functions, as I found this slowed down my online gaming immensly. Out of that bridge (router), it goes in to the wall and then any PC can use it with a phoneline card.
I think the chipset incompatibilies are the results of certain chipsets, probably VIA related because it works fine on an intel chipset motherboard. It is a well documented problem.