Cool script! An interesting alternative would be to find a site that offered lyrics in XML format and use XML::Simple to parse that. I don't know of any such sites, though.

Also, what do you do if the lyrics site doesn't have the song? Does WWW::Mechanize complain?

Here are a few pointers:

If you're going to do a substr() on a scalar and save the result into another scalar, you don't need to explicity copy the scalar first. You can just do:

my $firstletter = substr($artistsong,0,1);

Also, for translating something entirely to capitals, perl has a builtin:

$songtitle = uc $songtitle;