Selecting cells in a formula based on the format of the cell

I have a customer list my wife has provided me with to do a mail merge within word with but the catch is she only wants the mail merge done with the cells that are bold within Excel so I need some way within a formula to return the formatting of a cell. Ultimately I want to copy the bold cells into a seperate sheet and from there the mail merge is child's play.

Does anyone know how to test for the formatting of a cell within Excel? Also what would be the best way to use this as a test and copy the cells that meet the test over into a seperate worksheet?

Thanks in advance,
Jason