Don't know if you've noticed or not, but if you submit text with an apostrophe (') in it, you'll get the following:
I\'m going to the fair t\'day.
The way to fix this is to run the strip_slashes() on the variable holding the text from the textarea:
strip_slashes($comments).
That will remove the unnecessary "\" in front of quotes & apostrophes. PHP inserts them because it's the default escape character.
And this isn't a mail() function problem, it's just general PHP so you know.
~Brett