dividing text in parts

[anneCAT]

hi there,
Here's what i wanna do,
i wanna divide text in parts,so that each part contains exactly 100 words,but if there is paragraph,then size of that part will increase till end of paragraph,so that paragraph should not be broken in the middle. Can some1 give me solution for this.
Thanx...

[NogDog]

Some clarifications may be needed:

How will "paragraph" be defined in this text: HTML <p>...</p> tags, 2 or more consecutive newlines, 1 or more consecutive newlines, etc.?

Is dividing by number of "words" what you really want, or is number of characters better? (Words can be variable in length, plus number of characters may be easier to determine.