If you want a registered trademark, you submit to the US Patent and Trademark Office. Start here: http://www.uspto.gov/web/trademarks/workflow/start.htm If you want to register the copyright, you submit to the US Copyright Office. Start here: http://copyright.gov/
Note. There is a HUGE difference between Trademarking and Copyrighting something Simply publishing something and claiming the copyright ( assuming it is really yours to claim copyright on ) provides you with a legal copyright under the DMCA Trademarking is something completely different and must be filed for in the specific jurisdiction you want the trademark in For example, microsoft has their products trademarked in MANY countries, NOT just the USA. I hope this info is helpful to you Cheers Ron