Yep the adword tool is great for this purpose, or you can use any keyword density analyser to do exactly the same thing, I mean "enter a url and hit submit, then get all the keywords"
There are tons of such free tools online, just go to google and search for "free keyword density analyzer"
Here are two I've found and tried while answering :
hxxp://tools.seo*book.com/general/keyword-density/
hxxp://www.creating*online.com/site_promotion/keyword_density.htm