I used to get them all the time. But there are some ways of dealing with them -- some of them are tricks, some of them are changes in the way you see things.
First of all, you may be taking yourself too seriously. In the long term, absorbing this idea will probably do the most good. (Thank you, dannye.) I'm working on this one.
But there are often more immediate concerns -- confronting and changing the way you see the world takes some time and hard questionning, and you don't have time for this if you are panicking. To stop one that is in progress, try focusing on the word:
LIMP
Just focus on the word until it becomes the only word in your mind. Don't even say to yourself: "If I do this, everything will be okay." Just focus on the word: LIMP. It works.
You'll feel a little less afraid of the panic attacks when you understand that there is a way out. They do go away, and you didn't die the last time it happened. Try watching your thoughts during an attack -- step back and look at the thoughts, without feeding them. If you are able to step back like this, you'll notice that they go away of their own accord. They need to be fed in order to take you over, as they do during a full blown attack. Detach and watch them, and they can't grow.
Remember the panicked thoughts. Write them down. When you are more calm, go back and look at them. You will learn many, many things about yourself this way. You may be more irrational, and also more imaginative, than you ever imagined. Yes, this was you thinking these things. Get used to it. You may even learn to laugh about it.