Time handling in pgsql.

Hi,

I have a table like so.

create table times (
  start datetime,
  end datetime,
  estimate fload);

I'd like to be able to do something like this

SELECT estimate::timestamp - (end-start) from times;

anyone have some suggestions ?

When i do "select end-start from times" it formats
the text in such a way that it's like this

"1 days 2:33:03:00"

is there a way taht i can cast that to say "x seconds"
or 26:33:03:00 something like that is much more plesant
to parse than the 1 days format.

Thanks.

Jeff.