Help!Opening another php file from a link of a completed form.

I'd like to achieve something like this: I've made a form let say "a.php" and when user submitted it, the following code display the thank you page: // Form completed echo "Thank you! Information entered."; echo "Please click <a href='http://mysite/a.php'>here</a> to input another product."; echo "Or click <a href='http://mysite/b.php'>here</a> to input the details of your product."; I've made a blank (uncoded) page of "b.php" and one of the field is product name. If i want the "b.php" page being opened up with the product name already filled with the value entered by user in "a.php", what should i do to achieve it? Please help!! Thanks Edith Lai