you can find the css for the category listing for you theme in the defaults.css.
you will need to confgure the video services like youtube, go to the acp->community->media->settings, you will see several tabs there. on the general and category tab you can tell it which apps to ignore and which nodes/subnodes to ignore. on the services tabs, you will find links to how to get their api keys and how to configure them to work.
OK I am still having issues. I adjusted everything and I am still getting it off center. I just want any image auto sized to cleanly fit at say 90px by 90px. I adjusted in all three areas and kept messing with it and and the line setting and the size changes in both places and still looks weird.
As for the auto topic I am assuming this is for if someone posts in a certain area that can be grabbed and added? But is there a way to auto topic INTO a forum when a video is posted in the media application itself? Is there any RSS settings for this application?