Just use the 24 hour clock, making sure your cells are formatted to display the time as 1:30. If you wanted to write 1:30 PM, you'd just type 13:30- the cell would automatically display 1:30 PM. Typing in 1:30 would show up as 1:30 AM.
Thanks folks. I tried adding .5, and when combinding it with a if statement, it worked like a charm. I wanted to use the 24 hour setup, but the people who will be filling this out couldn't understand how to do it.