No, Google does not crawl the iframe content. To know more about the frame usage and SEO, please go to http://searchenginewatch.com/2167901
no google doesnt crawl i frame content. The page itself will be cached but it will not follow onto the frame src's So all google will see is the <title> and anything in the <noframes> and thats how it'd included in listings.
No, iframe is something that Google does not like at all. There are so many alternatives to iframe than why to go for it?
Its useful info for me. Recently Adsense banned my one domain because of trademark infringement .lol Now I will use frame at that domain from other hosting
Well, I don't think using Iframe is useful for SEO as google currently don't crawl Iframe. But may be in coming updates it start crawling Iframae too as it started flash files.