I have the following partial spreadsheet:

Date Total Hours Compensation
1/15/2008 11.00 $133.43
1/22/2008 12.15 $147.38
2/8/2008 12.00 $145.56

Is there an IF function that can be used to calculate the running total
Compensation by month without using the subtotal function? I would like this
total to automatically calculate when data is added to the spreadsheet.