Neregate.com puts out an awesome anime chart as images every new season airing in Japan. For example, here is the upcoming/current Summer 2013 Anime Lineup!
Just a slight warning on this site – it can contain some mature images, so browse carefully.
Also, another VERY helpful site is AnimeCalendar. It lists all anime and when it is airing in any given time zone (you can set). It’s really helpful for catching simulcasts!