log file conversion (OT?)

Wed Nov 9 17:35:56 GMT 2005

I have Squid running on a FreeBSD system and the log file (access.log) 
has lines like

1131556815.537    101 172.16.2.153 TCP_HIT/200 35674 GET 
http://www.urprize2.com/adv77/images/header_08_23_05.gif - NONE/- 
image/gif
1131556815.584     47 172.16.2.153 TCP_HIT/200 1828 GET 
http://www.urprize2.com/adv77/images/timer.swf - NONE/- 
application/x-shockwave-flash

in it.  Is there a simple way or a one- or two-liner script that can 
take the epoch time in the first column and replace it with the actual 
time/date stamp in human-readable format?