I’ve just setup OpenVPN on a windows xp machine, and found out that there are both good and bad sides of it. Good thing is; if you do not deviate from the well known scenario, follow the howtos, you’ll mostly make it fairly easily on windows.
Bad thing is; I rarely stay within well known scenarios, and I wanted a bridging setup. This means creating a virtual adapter and bridging it with an existing phsyical adapter. Lesson learned: on a windows machine with 2 nics, choose the one with default gateway to internet for bridging with the virtual adapter. You can use the other nic too, but I could not figure out how to connect that subnet to internet so that I can relay all traffic over vpn.
Routing seems to be a little hard to configure in MS, or with a better description of situation; I could not see many docs that migh help me out in this specific context. Anyway, I got it working, and I’m pretty happy with the performance. I’ll try to fix that subnet routing issue too.