This thread on use.perl.org points to some cool vim support for Perl. I'm not sure I like all the doodads in perl-support.vim, but I did add this to my .vimrc: 

autocmd FileType perl :noremap K :!perldoc <cword>
    <bar><bar> perldoc -f <cword><cr>

Now hitting K in vim runs perldoc or perldoc -f on the word under the cursor.