How to set up VPN Server

I would like to set up a VPN so that I can access my PC, network, and printer remotely. I am using Windows Server 2003. I also have a Linksys wireless router/firewall (I think this is preventing me from being able to get through). I would really appreciate “step-by-step” instructions starting from the beginning on how to do this. I think I need to open a port on my router, but I am not sure how to do this. I would like to be able to access my PC from anywhere on the internet by just typing in an IP address. Do I need terminal services to do this? I don’t want to have to install any additional software on other peoples computer just to access mine at home.
Thank you in advance for your help.