Count how many times a given date falls between date pairs

I'm trying to use countif or similar to show how many times a given date is between 2 dates (inclusive).

Each row of the spreadsheet contains amongst other info, a Start Date and an End Date. If i've got 2 rows like this:

StartDate EndDate
01/01/2009 03/01/2009
02/01/2009 04/01/2009

I'd want to lookup 02/01/2009 and have it return 2 (02/01/09 falls between the dates on row 1 and the dates on row 2).

To give some context, this is an export from a database containing staff holiday dates, and I'd like to be able to see how many people will be on holiday on any given date, given the start and end date of all holiday occurances throughout the year.

Any help would be much appreciated.