Subtracting two dates and times

I'm trying to find out how to subtract between two dates and times in seperate cells to determine the time between the two in days, hours, minutes.

For example, cell B1 has '1/19/2005 8:45' and cell A1 has '1/12/2005 10:22' so I need to get B1 minus A1 to display properly the time between the two in days, hours, minutes.

Thanks in advance for peeps help and advice!