guest e-mail length

Hello,
Our guestbook will only allow so many characters in the guest's e-mail entry. How do I change this?
Thank you!

You should find a line in form.php that looks something like:

input class=inputbox type="text" name="gb_email" size="xx" maxlength="xx"

In mine, although I've changed the code a bit, it's around line 100

Just change the max length field. I've used 50. You can also change the size field if you want.