Apostrophe Problems Options

[jamesjohnson88]

Whenever a form is submitted to my DB, if it has an apostrophe in it my MySQL throws an error. This is the code -

$con = mysql_connect("localhost","u08105199","edited");
if (!$con)
{
die('Could not connect: ' . mysql_error());
}
mysql_select_db("u08105199", $con);
// Get values to insert.
$sql="INSERT INTO contactMe (FirstName, LastName, Age, Email, Comments)
VALUES
('$_POST[firstname]','$_POST[lastname]','$_POST[age]','$_POST[email]','$_POST[comments]')";

if (!mysql_query($sql,$con)) //Function is called.
{ // IF statement to check for errors.
die('Error: ' . mysql_error()); // Error checking feedback.
}
else
{
echo ("Thank you, your comment has been added."); // Feedback message.
}
mysql_close($con)

I know I have to do something with escape strings but I just can't get my head around what parts of the code needs changing.

Any help is appreciated.