in reply to Another regex needed

Have you looked at HTML::FromText yet? It doesn't handle italics, but it might be all that you need: 
use HTML::FromText;

print text2html(
   'Hi there *mom* and _dad_',
   bold      => 1, 
   underline => 1
);

[download]

jeffa

L-LL-L--L-LL-L--L-LL-L--
-R--R-RR-R--R-RR-R--R-RR
B--B--B--B--B--B--B--B--
H---H---H---H---H---H---
(the triplet paradiddle with high-hat)

In Section Seekers of Perl Wisdom