Aaron at SEO Book mentions a site called SEO Digger which has a free competitive analysis tool that catalogs keywords a website ranks for.

Alternatives tool are: URL Trends, KeyCompete and SpyFu. All these domain tracking tools will help you download the keywords and adwords used by your adversaries.

Author

Navneet Kaushal is the founder and CEO of PageTraffic, an SEO Agency in India with offices in Chicago, Mumbai and London. A leading search strategist, Navneet helps clients maintain an edge in search engines and the online media. Navneet's expertise has established PageTraffic as one of the most awarded and successful search marketing agencies.