Too late to apply for Fall 2011? USA?

You could still apply but then your chances will be much lower than if you applied with the first rounds. If you think that you have a strong candidacy, it is worth of the try. But then you have to remember that most applications are quite extensive. You need to answer short questions, essays, get recommendations letters, transcripts, GMAT and so on. Can you get it all done quickly? The rushed application might not be as strong, and if you get rejected this year, it might be harder or impossible to apply next year (some schools don't like the rejects to apply again. Other don't mind). So you need to consider all these aspects. But you could still try. It really depends how confident you feel. People do get accepted in the last rounds after all. At least you can check out the application process and all requirements. And then take it from there.

State schools often have deadlines that extend far out into June... you could try. Depending on your profile, it may be realistic.

I think I'll wait, it's probably not worth the trouble. I might get into a better school next year. It's just that I'm now beating myself up for not applying for this fall.

At least now you have time to nail your applications and among the first ones! That also increases chances for a scholarship as scholarships tend to decrease with each round. You also have time to increase your working experience, improve your resume and do sometime extraordinary that will catch the admission's attention even more! Good luck!