if you say so......From past experience it is tough to get working well. Although I havn't done it recently, using something that requires realtime, time sensitive input doesn't work so well via an input card. The time the computer takes to convert the signal makes it awfully frustrating to play a game. If you can get a convertor that would do the trick assuming it would go directly to the monitor, but in all honesty for the cost of an adapter like that, just buy a tv. This really isn't a viable solution for playing video games without a tv. It isn't even that it would look bad on a computer screen, it lags which is the issue.
There is this little box thing you can use to connect VCR, DVD, PS2, Xbox, etc to your computer monitor...I can not remember wth it is called though. It is a box that has selectable inputs on it for your monitor. You basically connect your vid out from your computer to a VGA connection on it, as well as whatever other devices you are using through S-Vid or RCA and maybe even some component connections, then you can select which input to use for it. Best Buy sells it. Will try to remember the name and post back if I do.
I said that would work, the issue being cost. Here is one for 90 bucks that I found pretty quickly. Also its composite to vga, for what he wants.If all he wants to do is watch his PS2 on his computer MONITOR, why bother going through the computer at all ? Just go straight to the monitor as per my suggestion of the Component-to-VGA cable ...