Heres my punt. copy this formula into the cells to the right of your source data, fill it down and then sum it up. I think it works.
=VALUE(LEFT(H4;SEARCH(".";H4)-1))+(VALUE(RIGHT(H4;2)))/60
(BTW im using a Swiss version of Excel. I think in an english version the semi-colons should be commas.)
[ 14 August 2001: Message edited by: Mishandled ]