I am contemplating renaming the directory /techtalkforums/ to just /forums/ but I am very concerned with SEO. Of course, I would do a 301 redirect for everything in the directory. However, how guaranteed is that alone? Will the google toolbar PR eventually carry over and how long does it take to do so?

I am aware that a 301 redirect tells the se's that the pages have permanently moved to a new location and therefore *theoretically* carries over all their ranking. But I don't care about theoretical I want actual

I sell text links as the majority of my site's revenue. Even though *I* may know that I am using 301 redirects and the search engines will catch on, I'm not sure my advertisers will be so keen on being on a messload of PR0 pages.

How long will it take for the new URLs to be fully indexed?

I think that I need to add that my reason for wanting to rename the directory is purely "cosmetic" and to better reflect that Tech Talk is now only one section of my site (unlike it used to be back in the day).