Most, if not all *NIX-based systems store time and date values as epoch, means in seconds after a certain date, usually the seconds passed since 00:00:00 UTC Jan 1, 1970. Not a perfect approach, but sufficently accurate for most purposes. If you are confronted with such a value, then there are a couple of apporaches to convert it to something meaningful. The easiest way (again, on *NIX-based systems) is the following command:
date -r epoch_seconds
it returns a date-string readable by humans (and other beings familiar with the time-system used on earth). An example says more than any complicated explanation:
$ perl -e 'print time."\n";'
1157445071
$ date -r 1157445071
Tue Sep 5 10:31:11 CEST 2006
BTW: The perl-comand shown above comes handy if you need to know the current time in epoch-seconds.
But, the fun doesn’t stop here. Recently I had to convert epoch-times and do some calculations with it. Lazy as I am (you already got that, didn’t you), I decided to use AppleScript to do the calculations, but since I could not find an AppleScript-function capable of converting epoch-seconds, I used its capabilities to access the *NIX-brain beneath the pretty GUI. Without further ado, here is a handler to do the calculation:
on epoch2datetime(epochseconds)
set myshell1 to “date -r ”
set myshell2 to ” \”+%m/%d/%Y %H:%M\”"
set theDatetime to do shell script (myshell1 & epochseconds & myshell2)
return date theDatetime
end epoch2datetime
The return-value is fit to be fed into an AppleScript-command which converts it into a date-time value AppleScript can work with.
Hope this helps. 
BTW: I’ll try to figure out how to color the AppleScript later. Be careful if you do a copy and paste with the code shown, Wordpress insists on messing up the quotes, sorry.
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