In the Wall Street Journal's Small Business section, I found good information about trademark registration.
First, consider your company/product name. Names that are too generic "Farm" or too descriptive "We Make Robots" are hard to protect. Also think about what you are trying to trademark. Ideas cannot be trademarked. If you have created a unique process, then it may qualify for a patent.
Second, do some research. Check the U.S. Patent and Trademark Office's Web site, http://www.uspto.gov/ to see someone else has already trademarked the name.
Online trademark registration costs between $275 and $325 and asks for information such as the categories of goods and services for which the mark will be used, date of the mark's first use in commerce and whether there's a design component to the mark you're seeking. Internet businesses registering their names should generally refrain from registering their Web extension, such as .com or .net, with their name, unless they're planning to register the mark both with and without. Getting a trademark without the domain extension will help prevent other businesses from registering the same name by just adding a different extension, Mr. Stim says. He also recommends not designating a specific design of your trademark in order to get the broadest protection.