Hi jmbolanos
I'm not sure if I understand you right: you want to place a terminal somewhere in SL that would create an account in your OpenSim grid of specific users clicking something on it with their exact same name? What about the password? I would not feel well typing my SL password to some script
Besides of that this would be not impossible but also not easy to do, I have some worries what Linden is thinking about that

... taking away their few left users in such an easy way *g*
On the other side, SL users still will have to get either another viewer and add the connection to it or change some startup parameters of their existing one to switch over to your virtual world. So either way it will be more than just a 1-click issue for them ...
Greetz
FoTo50