need a little help with time

[nephish at xit.net]

Hey there.
i have a time string (created with strftime) then read from a file,
i am having some trouble understanding how to get the difference
between times.
i know i can structime(timestring) and get a time value, but i dont
know how to manipulate it.

basically, if i have string 2005-08-24 09:25:58
and another string 2005-08-24 09:28:58

how can i tell how many minutes, hours, seconds, days, months etc..
have passed between the first string and the second ?

or, if there is a good tutorial on this kind of thing, please post a
url.

thanks

shawn