Minutes in an interval

Hi!, Evrybody there!

How can I know how much minutes (or hours, or days) are there in an
interval. I mean:

Field T1 value: 01/05/2000 09:00
Field T2 value: 01/05/2000 10:00

T2-T1 gimme 01:00
the function date_part('minute',T2-T1) says 00
But I'd like to get 60
Is there a standar function wich tells the diff. in seconds/minutes or
whatever in an interval.

Now I'm using date_part('epoch',T2) - date_part('epoch',T1)

I had a function in MS SqlServer: datediff(string,date1,date2) --> Integer.
That's what I'm seeking.

By the way, the MS SqlServer  went to the hell and I replaced in one day and
one night by the PostgreSQL server I had for testing purposes (The backup
file gave me an unrecovery drive support in the restore of the MS SqlServer
(????!!!!)).

Think we are more than 100 workstations in a 24H / 7 days factory
enviroment.

Since then evrything goes faster and nicer.

Thanks in advance!

Pablo.