The reason I got interested in this in the first place is that the article I read made it sound like you didn't need to install client software on a Windows box to connect to an SSL VPN. However, this appears not to be correct. It looks as if I'll need to use either PPTP (PoPToP) or IPSEC (Free/SWAN) to do that, yes?
You normally have no need for client software - you have an openvpn box as the gateway, and all traffic on the vpns is compressed and encrypted transparently to the end user.
We have a number of businesses that use openvpn to connect remote offices to main office lan, without any client vpn software -
Joe