Because it's something I do often, and something my father always (and still does) insisted I shouldn't, I post the following stat on beginning a sentence with "and," taken from an article in the New York Times today.

The new one is the most significant revision since the 12th edition in 1969. It is the first edition, for instance, to address electronic publishing seriously. It also has the manual's first chapter on grammar and usage, written by Bryan A. Garner, with instructions on whether it is all right to use "and" and "but" at the beginning of a sentence. "And" has been O.K. since Chaucer's time, Mr. Garner said.

"The shibboleth persists that it isn't," he said. But the great grammarian H. W. Fowler, author of Modern English Usage, called it "a monstrous doctrine," he said. Mr. Garner, himself the author of A Dictionary of Modern American Usage, did a study on the issue. "Ten percent of sentences in first-rate writing begin with `and' or `but,' " he said..

Take that, Dad.