Auto delete pre-form entry text?

I added a product option so users can enter Personalization to their sign. Is there a way to make the text in the text box disappear when they start entering their personalization instead of having to delete the text first. I have seen this done on most entry forms on the web, and all you have to do is click in the text box and it either highlights or disappears immediately so you can enter your text.
Just a little details that would make it easier for user entries.

products_detail.php?ProductID=76

Thank you WA.

you could do this by editing the webassist/plugins/shopping_cart/add_to_cart.php page and adding:

onFocus="this.value=''"

to the option text box.

Worked perfectly!

As Always - Thank You Jason and WA.