Google's note on crawling framesets
To crawl framesets and their nested frames, the framesets must be well-formed with the tags occurring within the tag. Anchors (links) must also occur within the frameset. Depending on the particular structure of your site, the search results may point to the frameset page itself or to the individual frame pages. There is currently no way to specify which behavior you prefer.Sort of says it all... don't rely on the engines to handle frames correctly. Frames = poor SEO due to the unpredictability involved and lack of content on the actual page - the content is in each frame, which makes each one of those more valuable than the overall page but also much less useful to someone landing there.
It's been years since I've used actual frames for a design, but since the question gets asked quite often it seemed worth commenting on, especially since I was able to pull the information straight from the big G.