how to format archive date?

What do you mean?

right now my monthly archive is:
february 2004
january 2004
how can i make it:
feb 04
jan 04

In wp-config-extra.php, you will find a $month[] array starting around line 15 (version 1.0.1). Simply change the values of the full month names to what you’d like.

Where do I find the month array in 1.2? There’s no wp-config-extra I’m afraid.

It’s locale.php in wp-includes now – just found it ??

This still seems to change the date site wide and not just in the archives list in the sidebar.