Huh? Not sure how it would have anything to do with spam. Search engine spam is attempting to trick the search engines, generally by showing them something other than what the average site visitor sees.
I saw your posts mentioning higher rankings achieved in Google for keyword which was spelled wrong.
Is that spam or not spam?
I don't think that misspelling something on your page is trickery, nor spam. Might look dumb to your site visitors though, so I wouldn't recommend it as an SEO tactic, personally.
Do you have an idea how much it could impact the Google's PR?
Since PageRank is only about the quantity and quality of links pointing to your site, misspellings have zero effect on it.
P.S. Welcome, sri_gan!