Is it true that blogspot's blog pages get indexed very fast? And how to do that(fast indexing on google)?
I don't think blogspot gets indexed any faster than other blogging platforms. To get indexed, however, write often, use ping services and submit some of your articles to digg or reddit.
What does that have to do with anything? The free blog services that each provide are sub-domains, completely separate of the root domain. They all start with no PR at all. Another thing, PR does not govern how quickly or slowly a website gets crawled. One thing that does govern crawl speed is new content.