Are they still in? I believe the answer to that would be a big, "NO!"
XHTML Strict doesn't even have support for proper "frames" as the way you are thinking of (the "target" attribute doesn't exist anymore). The W3C has moved on to
XFrames, which is a little bit different.
As to if frames are even a good idea, I've seen them used effectively, but there is at least one HUGE disadvantage to using them: The end user can't (easily, anyway) link to an individual page on your site. A better option is to probably use server-side-includes to include any common elements in the same place across all pages, so you don't have to worry about frames.