When I do start trying to create a world using a more systematic method I tend to end up a little frustrated. Most worldbuilding methods seem to assume you already have a story in mind and start asking questions about mood and things. I tend to get mood for my stories from the setting rather than the other way round. I guess that's my fault for being all topsy turvy in the way I do things.
It gets more interesting when you're writing Contemporary Fantasy and similar. If your fantasy is set in the real world (or more accurately an approximation there of) then you'd think there's not a lot of worldbuilding to be done. Hum - wrong. You may not have to create Britain (or wherever you're setting your story) but if you have speculative elements you need to work out how they fit in. Secret cabals of psychic, werewolves, wizards, vampires, purple people eaters or whatever need coherent explanations of their subcultures and explanations of how they remain secret. Now these may never make it into the story (just like research and backstory you include only as much as is needed) but they are necessary so you know what's going on.
- Contemporary Fantasy: Setting the Fantastic in the Everyday World is an interesting article about the advantages and pitfalls of writing Fantasy set in the real world.
- Fantasy World Building Questions - an excellent starting place for developing a brand new world from scratch.
- 30 Days of Worldbuilding - I tried this once. Got flu in the middle and kind of let it slide. Got a lot of good stuff out of the exercises I did do though.
- The Rules of Quick and Dirty Worldbuilding - Exactly what it says. Five quick rules to bear in mind if you need to throw together a world quickly.
- Virtual Verduria - A exhaustive example of of a Worldbuilding Project with hints on map making and conlanging. Sometimes just looking at a good example is the best way of learning.