that's the long and short of it, yes. Having video-in (say, a VIVO card) or a capture card, and software capable of displaying the video-in signal appropriately will be sufficient to connect your ps2 to your pc.

But I'd ask myself, if I were you, "what am I trying to do".

If you're trying to record demos or something, that's the way to go.

If you just want to play games on your computer monitor, you might consider getting yourself a vga box. If you do video-in, you might suffer some quality loss (since you're going through extra steps and a whole video capture and redisplay process to get there). In my experience, it's tolerable, but it's not really great. PS2-compatible vga boxes can be found as cheaply as $30 (search froogle).

Also, consider the audio. If your sound card has a line-in, you can feed the ps2 audio into that (via RCA to minijack y-adapter), and use your computer's software to mix the audio. Otherwise, you'll need to switch audio via some other thing.