Edit /etc/bashrc, and add the following:
export HISTTIMEFORMAT="%Y%m%d %H:%M:%S"
Voila!
# history
...
368 20100323 20:46:17 vi /etc/bashrc
369 20100323 20:46:30 exit
370 20100323 20:46:35 date
371 20100323 20:46:36 history
...
#
Archive for February, 2010
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February 23rd, 2010