This can be done a couple of ways. One way is to place one of the dimensions on the text shelf (as opposed to a measure). Another option is to create a "blank" calculated field. It would simply be a space between two quotation marks:
Then, place this on the text shelf, and on the columns shelf. Then, right click on the calculation on the columns shelf and un-check Show Header.
Hope this helps!
Thanks, that's really helpful. Knew there had to be a way!