Charmaine Clancy's W is for World Building Workshop can be read online or downloaded in .pdf format.
Denyse "Domynoe" Loeb's Alden.nu has five world-building outlines along with tons of other templates and lessons here.
Encyclopedia Mythica offers info and articles from A to Z on mythology, folklore and religion to help inspire and populate your fictional worlds.
Evidently pantsers can world-build, too, just in reverse: Kat Zhang's Backwards Worldbuilding.
For obscure words and vocabulary resources, you can't do much better online than The Phrontistery (warning, wordsmiths, highly addicting site.)
How to Draw Nice Maps
Kathy Steffen's article Jump-Start Your Imagination: Creative Writing Exercises for Worldbuilding offers a list of questions you answer about your world as building exercise.
Loren J. Miller's Mythopoets Manual covers in exquisite detail the many things writers might consider when writing the multi-cultural fictional setting.
Orion's Arm states their
manifesto as "...to inspire writers, artists and thinkers. To create a
vision of the future that is plausible at every level, internally
consistent and abides by the accepted facts and theories in the
physical, biological, and social sciences." Some decent examples for
hard SF world-builders.
Stephanie Cottrell Bryant's 30 Days of World building tutorial can be read online or downloaded in several different formats, and covers a range of topics interesting to world builders.