The date format information for Joomla! 1.5 is stored in the file <Joomla! home>/language/<your language>/<your language>.ini. For example, for English, it is <Joomla! home>/en-GB/en-GB.ini.
To change the date format, find and edit the values "DATE_FORMAT_LCx". By default, the date is in international format (for example, Thursday, 31 January 2008 18:30). To change to standard US format (for example, Thursday, January 31, 2008, 06:30 PM), make the following changes:
DATE_FORMAT_LC=%A, %B %d, %Y DATE_FORMAT_LC1=%A, %B %d, %Y DATE_FORMAT_LC2=%A, %B %d, %Y %I:%M %p DATE_FORMAT_LC3=%B %d, %Y DATE_FORMAT_LC4=%m.%d.%y DATE_FORMAT_JS1=m-d-y %Y-%M-%D=%Y-%M-%D %A, %B %E=%A, %B %e
These are the formats for the time
%H:%M = 00:00 through 23:59 %k:%M = 0:00 through 23:59
%I:%M %P = 00:00 am through 23:59 pm (I = upercase i) %l:%M %P= 0:00 am through 23:59 pm (l = lowercase L)
(Note that %P will print the lowercase am/pm indicator for your locale, which may be blank.)
%I:%M %p = 00:00 AM through 23:59 PM (I = upercase i) %l:%M %p= 0:00 AM through 23:59 PM (l = lowercase L)
Joomla! uses standard Linux date format codes. These codes are listed at the following link: http://linux.about.com/od/commands/l/blcmdl1_date.htm.