On www.USPTO.gov, there are links for patent searches. You can search through both issued and published pending applications. Try the basic search and put in various keywords that would be used in a patent describing your invention. You can also try patents.google.com or even just a plain Google search. Depending on the technology, you could look in technical journals or databases like IE Explorer. Keep track of any vaguely relevant references you find as you should disclose these to the patent office when you file a patent application.

Answer Applies to: Washington
Replied: 7/6/2011

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The US Patent & Trademark Office website. It is also a good idea use computer search engines such as Yahoo and Google. Searching is an open-ended process because one can always keep looking. Happy Hunting!

Answer Applies to: California
Replied: 7/6/2011

Disclaimer: The response above does not form an attorney-client relationship. This answer may or may not apply to you and should not be relied upon as legal advice. LawQA does not make any representation as to the expertise or qualifications of this attorney. This attorney may or may not be admitted to state bar of your state.

Conducting patent searches requires considerable skill and experience, and you probably cannot do this on your own without retaining counsel. There is no one web-site that you can use for this purpose, in part because you need to conduct a search not only for U.S. patents (and patent applications), but for foreign patents and patent applications. Furthermore, many pending patent applications have not been published and, thus, your idea might be covered by an unpublished pending patent application. For this and many other reasons, you also need to conduct a search of prior art literature, as well as patents. The United States Patent Office Web Site offers access to full text of patents issued beginning in 1976. Google patent search has access to over seven million patents. Similar sites are available to allow searches of European patents and patent applications and those from other countries.

Answer Applies to: New York
Replied: 7/6/2011

Disclaimer: The response above does not form an attorney-client relationship. This answer may or may not apply to you and should not be relied upon as legal advice. LawQA does not make any representation as to the expertise or qualifications of this attorney. This attorney may or may not be admitted to state bar of your state.

You can perform free patent searches at the United States Patent & Trademark Office's website, and just follow the patent links or via google.com/patents.

Answer Applies to: California
Replied: 7/6/2011

Disclaimer: The response above does not form an attorney-client relationship. This answer may or may not apply to you and should not be relied upon as legal advice. LawQA does not make any representation as to the expertise or qualifications of this attorney. This attorney may or may not be admitted to state bar of your state.

The US Patent Office and Google both offer free online databases of patents and published patent applications. A patent attorney can help you with a more in-depth prior art search and analysis of the prior art in view of the requirements for patentability.

Answer Applies to: Colorado
Replied: 7/6/2011

Disclaimer: The response above does not form an attorney-client relationship. This answer may or may not apply to you and should not be relied upon as legal advice. LawQA does not make any representation as to the expertise or qualifications of this attorney. This attorney may or may not be admitted to state bar of your state.