If you follow the topic for "Enhancing the Appearance of Tables" it takes you to page 84 "“Formatting Table Cell Borders” which describes what you want.
The manual is over 250 pages of very useful information and is a free download from apple. (I think its also on the install disk if you purchased the boxed iWork set).
Do you know how to easily print the gridline numbers in numbers? In excel it is simply a check in the box. For the life of me I can not figure out how to do this.
Numbers has no such checkbox or control. Wouldn't putting numbers in Column A do the same thing? You could hide column A if you didn't want to see the numbers.