The DVI Differences

Can anyone explain to me the differences between the 2 DVI standards? I picked up a monitor tonight and it has regular VGA connection and DVI connection. The DVI cable it came with has 18 pins and the slanted pin. Now my GFX card has a DVI connector on it and when I plug the DVI cable in nothing happens. Now researching the different connections and equipment I found that the card I am using now uses DVI-I, and the monitor is DVI-D. I looked up DVI-D cables, and I found out DVI-D, is 24 pin with the slant pin. Now is this how these are classified, and did I get the right info? If that is correct, are DVi-I and DVI-D interchangeable? Am I going to have to go out and a cable to make use of the DVI connection on my monitor?

 

dvi-i seems to be the new standars especially since high end dlp, lcd, and plasma tv makers have started using the format..... because every one needs that 9000$ 61" pioneer elite plasma hanging on the wall in front of their keyboard.........

 

Here's some info on DVI:
http://www.datapro.net/techinfo/dvi_info.html