poacher69, we crawl the public web. Anyone that blocks us out with robots.txt, we won't crawl. If you check bing.com/robots.txt, it has "Disallow: /search" . So no, we won't crawl Bing's search results pages. If anything, users tend to complain when search results from Lycos or wherever show up in Google.
I was gonna call out Matt for crawling bing's search results but I'm guessing Microsoft hasn't realized they return results from the /Search/ folder. ;)
From my experience, Googlebot doesn't crawl pages that are blocked in robots.txt files. Check out Bing's robots.txt: http://bing.com/robots.txt - notice how /search is disallowed. That typically means that Googlebot isn't able to access that page. The same for the other search engines, it's more down to if they specify (through robots.txt) that Googlebot isn't allowed to crawl those results.
