I think you've almost got it. I would suggest adjusting the format spec to pad the 2 digit fields with leading zeroes in the case of a single digit.

print sprintf("%4d-%02d-%02d %02d:%02d:%02d.000",
               Today_and_Now());
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That way you get:

2010-11-19 12:47:07.000 instead of...
2010-11-19 12:47: 7.000
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