Is there any website that lists the upcoming main chess tournaments? It seems that I only notice them as soon as chessbase publishes its first round. maybe I am missing something...

You can find a list of upcoming real life chess tournaments at http://www.chess.com/chess-tournaments where you can also search in your local area.

For USCF events, try uschess.org, or if you are just interested in the major international events, Chess Vibes has a calender of those upcoming, too.  The Chess.com calendar includes so many local events it is harder to find the biggies, IMHO.

You can search through these.

http://www.chess-calendar.com/#0

http://www.fide.com/calendar/tournaments.html

http://www.chessvibes.com/chess-events-calendar/