I have the Component Transcoder not the RGB splitter, but from what I can tell the Component Transcoder is a superset of what the RGB splitter can do.
The IV24 can do a number of things. It can act as a scandoubler, video card (though only through EGS), genlock and video grabber.
The scandoubler is pretty simple and can be controlled via the IV24 utilities or through the switch on the back of the card. The lower and middle positions both enable the scandoubler, though I'm not sure if there is a difference between the middle and down positions. Software control is achieved through the IVCP program.
Without a better idea of what you want to do with the card, it's hard to proceed further than this.