Using Excel 2008 (Mac) I want the hours shown in the x-axis not to be 1:12, 2:24, 3:36, etc but 1:00, 2:00, 3:00, 4:00, etc.
I guess you're meaning in a chart? If so you can edit the Major Unit and Minor Unit of an axis scale by right-clicking the axis and changing properties under Format Axis. Somewhat confusingly if you're working in time, the scale it uses is 1 day = 1, so you'll need to divide the day up into whatever time base you want. Looks like you want hour which is 1/24 or 0.041666667. Depending what values Excel guesses for minimum/maximum etc, you may also need to tweak these to suit what you want, in which case the same principle applies.