Here are good, basic sites about the other branches of government—remember there are hundreds more.

100 Milestone Documents 
http://www.ourdocuments.gov/content.php?flash=true&page=milestone
Compiled by the National Archives and drawn primarily from its holdings, these documents chronicle United States history from 1776 to 1965.

Executive Branch
http://www.usa.gov/Agencies/Federal/Executive.shtml
Links to the official sites of the agencies and departments of the executive branch.

Federal Judiciary 
http://www.uscourts.gov/
Clearinghouse for information about U.S. federal courts including news, publications, directories, and links to federal courts.

Judicial Branch 
http://www.usa.gov/Agencies/Federal/Judicial.shtml
Links to the official sites of the federal judiciary.

Presidents of the United States 
http://www.presidentsusa.net/
The most comprehensive site on the Internet for presidential resources. The alphabetized subject headings are linked to most of the sites on the web that have information about presidents.

Primary Documents in American History 
http://www.loc.gov/rr/program/bib/ourdocs/PrimDocsHome.html
The Library of Congress is home to many of the most important documents in American history. This Web site provides links to materials digitized from the collections of the Library of Congress that supplement and enhance the study of these crucial documents.  The initial release of this Web site contains documents from the years 1763 to 1877. Updates will be made on a regular basis, including the addition of documents from the 20th Century.

SearchGov.com 
http://www.searchgov.com/
This search engine provides links to federal and state government pages.

USA.gov
http://www.usa.gov/
As the U.S. government's official web portal, USA.gov makes it easy for the public to get U.S. government information and services on the web. USA.gov is an easy-to-search, free-access website designed to give you a centralized place to find information from U.S. local, state, and federal government agency websites.

White House 
http://www.whitehouse.gov/
The official White House site with information related to the history and current administration.

White House for Kids 
http://www.whitehouse.gov/kids/
Information and interactives about the White House and its occupants designed for young people.