To you can find a good niche keywords through using of Keyword Research or Keyword Trends. You may used the Keyword Research Tool like Wordtracker, Seobook and Google Adword Seo Tool. You may also try the Google Trends, Yahoo Buzz and MSN in checking the keyword trend.
From my side i wud say just go for few tools like: Google Adwords Keyword, Google Suggest, Google Insight to find proper keywords for your pages with searches around the world and in the particular country . To check the competition go through with these terms: Google Search Results of a keyword double quotes results of keyword like "keyword" allintitle:Keyword allinurl:Keyword By these terms you wud get enough knowledge about competition of a keyword.............
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