Customizable Text Fields

I own Acrobat Pro 8. I want to create a PDF document for our customers and have text field where they can enter their own store name, address and phone number. I have tried this by simply adding a text box and it seems to work, but when I then go to Acrobat Reader, change the text and try to save it says that I have to have Pro 8 in order to save the changes.

How can I create a text field that my customers can modify and save?

Thank you so much!
Eric