Dictionary

http://dictionary.reference.com/

http://encarta.msn.com/encnet/features/dictionary/dictionaryhome.aspx

http://webster.com/

Thesaurus

http://thesaurus.reference.com/

http://webster.com/

Encyclopedia

http://encarta.msn.com/encnet/refpages/artcenter.aspx

http://www.britannica.com/

Homework Help

http://encarta.msn.com/homework/

http://homework.com/

http://refdesk.com/