How do i write a formula to count the number of days in a date range, split per month

Hi, sorry if this has previously been posted and solved but the search funtion doesnt work on my browser at work.

I have a large spreadsheet which holds lots of data with date ranges that i need to performs different actions to. im currently trying to figure out a way to identify the number of days, per calender month, that falls in a date range.

sample data...

Start Date	End Date	Old Value	New Value
08/03/2010	18/06/2010	16758.2	16758.1
19/06/2010	04/08/2010	16758.2	-224147.3
05/08/2010	17/01/2011	16758.2	2923.1

i need to break down the total number of days per month

Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
		24	30	31	18
					12	31	4
							27	30	31	30	31

As you can see this also laps into a new year, which poses my next problem, ill probably just add more columns on to the end of the table for that though...

I will later apply different calculations to these cells but in short need to get a calculation for the number of days per month first.

(in short spreading the new value out accross the year then multiplying it by the days... i also need to apply a further daily volume cal to it)
can any one help at all please?

Ta
Ben