This is what I have found, I did some 301 redirects about a month ago. Yahoo picked it up fine, has been crawling the site for a week and following the redirects. however it had not indexed the new pages. Last night, all of my old links with redirects were dropped from the index and Yahoo did a major deep crawl of the whole site. The new pages have not been updated to the index, I would anticipate that this will take a week or so for the next update to start seeing them.