Using preg_replace to escape/replace Quotations

I have a User information system I
am working on, and so far I have
been stripping everything but spaces
from the information I insert and update
to the database.

I have an ultimate goal to place every
character one may use to create a webpage
within the fields in my database.

To get started though I would just like
to replace commas, quotes, parenthesis
and other characters with values that will
render as the correct character if just
echoed as output..

Are there any good class libraries in PHP
That I should look into to do this. I would
much like to use existing code in this case
than create my own, as I believe it could
take a little while...

Trying to proof my system for SQL
injection and unintended user action.

I've no trouble with ensuring data is
numeric, alpha, a combination of NumAlpha
and I can insure it is a certain length also.

My troubles exist with, Using comma's to
delimit field values, While still allowing the
user to have a comma within the field.

Pls. help