Emacs has a "mixed mode" which allows it to handle this sort of thing. I use it for editing Mason pages with in-line perl code.

Yes, you probably mean "mmm-mode"... it was originally written to deal with Mason (perl and html intermixed) so that case should certainly work out-of-the-box. In theory, with a little setup you can use this on any number of combinations (myself, I still need to look into how to deal with SQL embedded in perl heredocs...):

On the emacswiki:

MultipleModes

HtmlModeDeluxe

I could not tell you if something like this has ever been written for vim, but I have my doubts it would be that easy to do... certainly I've never heard of anything like it.

Obviously, I also like the emacswiki, and I tell people to check there first because for some reason the site doesn't rank very high in google searches. There's a page with pointers to different perl-related emacs projects:

PerlLanguage

(One of my fantasies is to someday set-up some kind of emacs bundle for people who want to use it to hack on perl...)