US State Department "Background Notes"- www.state.gov/r/pa/bgn- Some slightly redundant info, but you are going to find that anywhere that you go.
Country Profiles from "countrywatch.com"- http://embassy.countrywatch.com- Includes general infromation that would be ideal as a starting place.
Library of Congress Country Studies- http://lcweb2.loc.gov/frd/cs/cshome.html
Foreign Government Resources- www.lib.umich.edu/govdocs/foreign.html- Has links to some of the larger countries, but not to some of the smaller ones.
Comprehensive Database of governmental institutions- www.gksoft.com/govt/- Contains more than 17,000 entries from more than 220 countries and territories,
World Bank Country Profiles- www.worldbank.org/html/extdr/regions.htm- Just as you might be able to guess from the name, these are profiles about the countries economic conditions put out by the world bank. This is a must to go here if you are ever in the ecofin committee.
E-Conflict World Encyclopedia- www.emulateme.com- Geared more towards people that are in something like OAS or Security Council. Also fine for any sochum sort of committees.
Chiefs of State and Cabinet Members of Foreign Governments- www.odci.gov/cia/publications/chiefs/index.html- Seems to be down frequently "for repairs" but good when it actually comes up.
Constitutions of the World- www.uni-wuerzburg.de/law/home- A German NGO's contribution. (Yes, some of those countries DO have constitutions even if they don't follow them.) Use this for OAS, Security Council, and humanitarian anything.
Elections around the world: results and other links- www.electionworld.org/election/index.html- If you know that a country is having an election you can find the results here, but know that they certainly don't have all elections. Most of their info applies to national elections. Doesn't cover many small countries because of the lack of free elections.
International Statistical Agencies- www.census.gov/main/www/stat_int.html- If you need stats, they are here, but these are more humanitarian ones.
International corporations- http://faculty.washington.edu/sparke/resources.htm- Nice place for info on major corporations, human rights within them, and environmental NGO's.
MAPS- www.nationalgeographic.com/resources/ngo/maps/- While you can get some nice ones here, you can also go to the www.about.com site and look there too.
Global Policy Collection- www.globalpolicy.org- One of the most important things about being a good delegate is knowing where your country stands on certain issues. This collection provides you with links to different sides on major issues as well. To more easily navigate the site, it is helpful to go in with a specific topic in mind.