Online Dictionaries:

http://www.dictionary.com
http://www.freedictionary.com
http://www.merriam-webster.com
http://www.onelook.com/

Filipino:

http://www.tagaloglang.com/
http://www.seasite.niu.edu/Tagalog/Dictionary/reverse_lookup.htm
http://www.tagalog-dictionary.com/

Foreign Languages:

www.freetranslation.com
http://www.wordreference.com/
http://humanities.uchicago.edu/orgs/ARTFL/forms_unrest/FR-ENG.html

Math:

http://hotmath.com/
http://www.math.com/
http://www.purplemath.com/

Sciences:

http://www.kensbiorefs.com/
http://www.physicsclassroom.com/
http://www.s-cool.co.uk/
http://www.chemicalforums.com/
http://www.glenbrook.k12.il.us/gbssci/phys/Class/1DKin/U1L1d.html
http://www.cdli.ca/CITE/astronomy.htm

Media/Communication Studies, Journalism, and Creative Writing:

http://cmfr-phil.blogspot.com/
http://www.pcij.org/
http://www.absynthemuse.com/
http://www.uiowa.edu/~commstud/resources/
http://www.pbs.org/teachersource/media_lit/related_study.shtm

Politics, History, and Social Commentary:

http://www.quezon.ph/
http://www.joserizal.ph/
http://philippinecommentary.blogspot.com/

Philosophy, Psychology and Religion:

http://www.philosophypages.com/

Computers, Programming and Technology:

http://www.nethelp.org/symbolhelp/
http://www.programmingtutorials.com/
http://www.videohelp.com/

Higher Learning:

http://www.medterms.com/script/main/hp.asp
http://www.chanrobles.com/
http://www.bized.ac.uk/
http://student.ttuhsc.edu/JBuchanan/histology.htm
http://www.free-ed.net/free-ed/
http://changingminds.org/

General Learning,Forums, Fun Websites and Sites with good links:

http://www.studentcenter.org/
http://www.thinkquest.org/
http://www.wisegeek.com/
http://www.kiwibox.com/
http://www.peyups.com/
http://www.infoplease.com/
http://www.factmonster.com/
http://www.sparknotes.com/
http://www.bbc.co.uk/learning/
http://www.ehow.com/

Encyclopedias:

http://www.britannica.com/

Royalty Free Photographs/Images, Music, books and Free Web Tools:

http://www.dreamstime.com/
http://www.flashkit.com/index.shtml
http://www.flash-gear.com/index.php
http://librivox.org/
http://www.sxc.hu/