This is perhaps the only part of the immigration process, where things are actually made easy for you to succeed. The new 'history and civics' questionnaire format requires you answer 6 out 10 questions (these are all sitters, and strictly sampled from a bank of 100 that you can find online or in their booklet/CD). You then read and write a simple sentence in English. If everything goes ok, its a 5-minute process (thats it!). The process of document verification and other questions to ensure that you aren't a commie, criminal, or an extremist, you've paid your taxes, etc. takes about 10 minutes. Make sure you have your green card and driver's license for the state you reside in, to make life easy (else you have to provide other acceptable evidence of state-residency). Of course, if you are filing based on your spouse, additional documents that are required.