iPhone - How to determine in which cell a button was pressed in a custom UITableViewCell

I currently have a UITableView that is populated with a custom UITableViewCell that is in a separate nib. In the cell, there are two buttons that are wired to actions in the custom cell class. When I click one of the buttons, I can call the proper method, but I need to know which row the button was pressed in. The tag property for each button is coming as 0. I don't need to know when the entire cell is selected, just when a particular button is pressed, so I need to know which row it is so I can update the proper object.