Good questions; I've been thinking about the second question a lot lately, and I wonder whether others will add their own setups.
First question, though: gomtv
I don't know exactly how their model works, but it seems like without a subscription for the season, they'll occasionally open up given matches for replay afterwords, but this is where to watch them live. I've never looked for a way to get the actual match files, I don't know if they do that. For example, I haven't seen a replay in a daily that had the custom GSL decals on the ground, and if any one could get them, I would think the Day9 crew could. The live events typically come on at 02:10 here in the PST.
I'm more of a recreational player/viewer, so I don't automatically have every tournament memorized. A number of times, I've found out about something from Sean's Twitter feed, or the chat in the dailies. I think if you follow the big names on twitter, you'd get a pretty good sampling of what's going on.
However, my list of sites to keep tabs on are:
gomtv -> GSL (SK WCS stuff)
http://www.majorleaguegaming.com/ -> NA WCS stuff
dreamhack -> EU WCS stuff
and of course TeamLiquid, as so much information seems to filter through there. If I didn't include it, someone else would. The event sites always have either the live streams embedded, or linked. Finding the videos afterwards is usually just a matter of identifying the players and searching.
I also keep tabs on the AGHL.
I've got the gomtv app on my phone to easily check who's playing a given match to decide whether it is worth staying up. I would like a more comprehensive app, but that's waiting on some free time or volunteers.
I realize what I've described is more how I try to keep track of what's going on, which wasn't actually the question, but I think it is a logical extension of the question. Other's can maybe list some more specific tournament details.