I agree with all that say the declaration is binding and I do enforce it in our home games.
Originally Posted by Doctor Holdem
I would think you should be forced to call... AND unable to raise. You clearly declared you were playing, but allowing you to raise would be wrong as well.
However the statement is not clear enough to make a determination as to intent beyond putting chips into the pot. All that statement does is indicate that the player is in fact going to contribute to the pot. I've done this myself (though granted I wasn't out of turn), in which I've made a verbal statement meaning that I was at least going to contribute and in some cases raised. The only formal statements that are binding to specific definitions are "Call", "Check", "Fold", "Raise", and "Reraise". They all mean something specific to poker that is common knowledge and cannot be mis-interpreted. Anything else is only binding to the general action (as in will or won't be contributing chips to the pot).