Skip writing 0 hours?

Hello,
I am doing lists of songs: title, composer, etc and duration.
I wonder if it possible with Excel 2007 to enter the duration in minutes and seconds (mm:ss),
without always having to type first 00: for hh:?

xl wont know what ':34' is. (is it time, is it a budding list, a delimiter, etc)
but it does know time is: hh:nn

Thank you ranman256 for your answer.
I just wondered if there is a way to just write mm:ss instead of 00:mm:ss

Thank you kev_, this is a cool formula