This list contains all the two letter TLD's for countries and a few generic TLD's. Should keep you busy for a while, there are more where that came from.
.aero Aviation
.biz Business Organizations
.com Commercial
.coop Co-Operative Organizations
.edu Educational
.gov US Government
.info Open TLD
.int International Organizations
.mil US Dept of Defense
.museum Museums
.name Personal
.net Networks
.org Organizations
.ac Ascension Island
.ad Andorra
.ae United Arab Emirates
.af Afghanistan
.ag Antigua and Barbuda
.ai Anguilla
.al Albania
.am Armenia
.an Netherlands Antilles
.ao Angola
.aq Antarctica
.ar Argentina
.as American Samoa
.at Austria
.au Australia
.aw Aruba
.az Azerbaijan
.ba Bosnia and Herzegovina
.bb Barbados
.bd Bangladesh
.be Belgium
.bf Burkina Faso
.bg Bulgaria
.bh Bahrain
.bi Burundi
.bj Benin
.bm Bermuda
.bn Brunei Darussalam
.bo Bolivia
.br Brazil
.bs Bahamas
.bt Bhutan
.bv Bouvet Island
.bw Botswana
.by Belarus
.bz Belize
.ca Canada
.cc Cocos (Keeling) Islands
.cd Congo, Democratic republic of the (former Zaire)
.cf Central African Republic
.cg Congo, Republic of
.ch Switzerland
.ci Côte d'Ivoire
.ck Cook Islands
.cl Chile
.cm Cameroon
.cn China
.co Colombia
.cr Costa Rica
.cs Czechoslovakia (former - non-existing)
.cu Cuba
.cv Cape Verde
.cx Christmas Island
.cy Cyprus
.cz Czech Republic
.de Germany
.dj Djibouti
.dk Denmark
.dm Dominica
.do Dominican Republic
.dz Algeria
.ec Ecuador
.ee Estonia
.eg Egypt
.eh Western Sahara
.er Eritrea
.es Spain
.et Ethiopia
.eu European Union
.fi Finland
.fj Fiji
.fk Falkland Islands
.fm Micronesia
.fo Faroe Islands
.fr France
.ga Gabon
.gb United Kingdom
.gd Grenada
.ge Georgia
.gf French Guiana
.gg Guernsey
.gh Ghana
.gi Gibraltar
.gl Greenland
.gm Gambia
.gn Guinea
.gp Guadeloupe
.gq Equatorial Guinea
.gr Greece
.gs South Georgia and the South Sandwich Islands
.gt Guatemala
.gu Guam
.gw Guinea-Bissau
.gy Guyana
.hk Hong Kong
.hm Heard and McDonald Islands
.hn Honduras
.hr Croatia
.ht Haiti
.hu Hungary
.id Indonesia
.ie Ireland
.il Israel
.im Isle of Man
.in India
.io British Indian Ocean Territory
.iq Iraq
.ir Iran
.is Iceland
.it Italy
.je Jersey
.jm Jamaica
.jo Jordan
.jp Japan
.ke Kenya
.kg Kyrgyzstan
.kh Cambodia
.ki Kiribati
.km Comoros
.kn Saint Kitts and Nevis
.kp Korea, Democratic People's Republic of
.kr Korea, Republic of
.kw Kuwait
.ky Cayman Islands
.kz Kazakhstan
.la Lao People's Democratic Republic
.lb Lebanon
.lc Saint Lucia
.li Liechtenstein
.lk Sri Lanka
.lr Liberia
.ls Lesotho
.lt Lithuania
.lu Luxembourg
.lv Latvia
.ly Libyan Arab Jamahiriya
.ma Morocco
.mc Monaco
.md Moldova
.mg Madagascar
.mh Marshall Islands
.mk Macedonia
.ml Mali
.mm Myanmar
.mn Mongolia
.mo Macau
.mp Northern Mariana Islands
.mq Martinique
.mr Mauritania
.ms Montserrat
.mt Malta
.mu Mauritius
.mv Maldives
.mw Malawi
.mx Mexico
.my Malaysia
.mz Mozambique
.na Namibia
.nc New Caledonia
.ne Niger
.nf Norfolk Island
.ng Nigeria
.ni Nicaragua
.nl The Netherlands
.no Norway
.np Nepal
.nr Nauru
.nu Niue
.nz New Zealand
.om Oman
.pa Panama
.pe Peru
.pf French Polynesia
.pg Papua New Guinea
.ph Philippines
.pk Pakistan
.pl Poland
.pm St. Pierre and Miquelon
.pn Pitcairn
.pr Puerto Rico
.ps Palestine
.pt Portugal
.pw Palau
.py Paraguay
.qa Qatar
.re Reunion
.ro Romania
.ru Russia
.rw Rwanda
.sa Saudi Arabia
.sb Solomon Islands
.sc Seychelles
.sd Sudan
.se Sweden
.sg Singapore
.sh St. Helena
.si Slovenia
.sj Svalbard and Jan Mayen Islands
.sk Slovakia
.sl Sierra Leone
.sm San Marino
.sn Senegal
.so Somalia
.sr Surinam
.st Sao Tome and Principe
.su USSR (former)
.sv El Salvador
.sy Syrian Arab Republic
.sz Swaziland
.tc The Turks & Caicos Islands
.td Chad
.tf French Southern Territories
.tg Togo
.th Thailand
.tj Tajikistan
.tk Tokelau
.tm Turkmenistan
.tn Tunisia
.to Tonga
.tp East Timor
.tr Turkey
.tt Trinidad and Tobago
.tv Tuvalu
.tw Taiwan
.tz Tanzania
.ua Ukraine
.ug Uganda
.uk United Kingdom
.um United States Minor Outlying Islands
.us United States
.uy Uruguay
.uz Uzbekistan
.va Holy See (Vatican City State)
.vc Saint Vincent and the Grenadines
.ve Venezuela
.vg Virgin Islands British
.vi Virgin Islands U.S
.vn Vietnam
.vu Vanuatu
.wf Wallis and Futuna Islands
.ws Samoa
.ye Yemen
.yt Mayotte
.yu Yugoslavia
.za South Africa
.zm Zambia
.zr Zaire (non-existent, see Congo)
.zw Zimbabwe