I suspect one of the reason why the calendar for top level chess seems o crowded is that there are plenty of organisers still willing to hold such events. The World Championship match has just finished, but the Moscow will see another event beginning at the end this week, the 2012 Tal Memorial.
The top 5 players (according to the Live Rating List), Carlsen, Aronian, Kramnik, Radjabov and Nakamura are all in the field, along with Caruana, Morozevich, Grischuk, Tomashevsky and McShane. The 10 player round robin starts on the 7th June (with a blitz event to decide colours!), and runs until the 19th. I'm assuming that the tournament coverage will be almost as good as the WCC (live video commentary!?), although for now the only link to the tournament I've found is http://russiachess.org/ which is of course in Russian!
As for tournament tips, Carlsen and Aronian to battle it out for first, Caruana to be the surprise packet, and McShane to play the longest games of the tournament!