[tamarian]

Changing uppercase to lower case is easy. Many text editors can do it, so you can cut and paste into the text editor, then convert. It can also be done easily with PHP's strtolower function.

The grammer and punctuation part is the hard part. Doing it from scratch is a large project. But some word processors do have the capability. I used a program called Gammatica long time ago that plugs into word processors and does decent grammar check.

But if you mean just changing the capitalization to the beginning of the sentence, that should be easy.