Date::Manip is one module that's pure perl, and by the author's documentation, attempts to be the swiss army knife of date modules.
But if that doesn't help, a search on CPAN might. Last time I needed something to do with dates (earlier today, in fact), I did a search, read through some of the various module's documentation, and picked the one that made the most sense.
--chargrill
$,=42;for(34,0,-3,9,-11,11,-17,7,-5){$*.=pack'c'=>$,+=$_}for(reverse s
+plit//=>$*
){$%++?$ %%2?push@C,$_,$":push@c,$_,$":(push@C,$_,$")&&push@c,$"}$C[$#
+C]=$/;($#C
>$#c)?($ c=\@C)&&($ C=\@c):($ c=\@c)&&($C=\@C);$%=$|;for(@$c){print$_^
+$$C[$%++]}