Preg_Match to error out page on html tags

Experts,

I have a form which parses on message board post data to a validation page.  I am looking for a preg_match expression that will error out when it finds a < or > in a string.

code is:

if (!preg_match('???????', $_POST["t_title"]) || !preg_match('?????????', $_POST["t_body"])){
include (error.php);
}
else {
include (thankyou.php);
}

Thank you