Where on internet I can find the basic information about the trademark registration?
The online USPTO website, http://www.uspto.gov/main/trademarks.htm provides with your required information and offers the online e-filing of applications and documents regarding trademark. At USPTO there is a Trademark Electronic Application System (TEAS), which contains all the information needed for the complete registration process. You can also search the entire database of Trademark Electronic Search System for checking out the contradictory marks.