Most SEO tools can show you the keyword competition. Google AdWords External tool can help you with this. I use that along with Traffic Travis, a powerful SEO application. Hope that helps. Have a good day!
There are several tools as suggested in the above answer that can give you the details of the competitiveness of the keywords. Google Adwords is the most used and it delivers the result along with the comparison. Its pretty good for a better analysis, as far as I concern.
I would not use Google Adwords keyword tool, based on the fact that it gives little information. Try another program like Market Samurai or something.
A lot of SEO tools that you can use for this purpose. If you want to use online tools, you can try spyfu.com. This is very good enough for you to know your keywords competition.
I agree with trevepoli above. Market Samurai has an SEO Competition tool which gives you a detailed picture on the competition for a keyword for the top 10 spots on google, which is all that really matters. You can get a free trial of MS too. This is what I use to find low competition keywords.
AdWords Keyword Tool and other keyword checkers are great, but do check Google Trends as well: it will show you how much people search certain times over years... the trends are also important. It's surprising how some keywords are becoming less-fashionable, while others become more fashionable over time...
You signature saying you providing cheap SEO services & you don't know how to analyze the competition of a keyword ?
use google adword keyword tools then check competitor PR and Indexed link using seoquake. Normally after get csv from GKT I use seo spyglass to check it again. I have this tools in my vps service.
Keyword competition is the measure of how difficult it will be to rank for a particular keyword. The competition for a keyword can vary depending on how popular the keyword is and industry competition