That's a pretty general statement. If you are talking anime cons, the only two I know of are No Brand Con and Anime Milwaukee (which was March 12-14, and I would have posted it if I had know about it sooner. It was fun

). Out here at UW Platteville, we had our Plattecon at the beginning of March, but that was more for gaming, not anime. Wisconsin just isn't a good place for cons I guess.
Pre-registration for No Brand Con has been extended to March 31st
BTW I saw Todd Haberkorn and Wendee Powell at a VA panel at Anime Milwaukee. They are worth going to see.