“Alice” Room Makeover – The Steampunk Home has some suggestions for decorating with an Alice in Wonderland theme.

Bat Mobile – Instructions and pattern for making a cute hanging bat mobile out of cardboard.

Day of the Dead Embroidery – Gorgeous embroidered version of a pretty Catrina painting.

Horror Decor, Rough Night Collection – Blood-spattered bedding. This would be fairly easy to DIY with fabric paint. (Hat tip to Kitten Herder)

Cthulhu Blankie – Adorable little crocheted baby blanket with extra tentacly goodness.

Blood “Energy Potion” – Fruit punch-flavored energy beverage with the same color and consistency of blood. Packaged in a resealable transfusion bag.

24 Crafts in 24 Hours – The Swell Life is going to try to complete 24 different Halloween crafts in 24 hours on October 8. This will be a great source of quick and easy craft ideas.

And some sites that will be doing Halloween themes all month:
Countdown to Halloween
Dave Lowe Design (and Para Abnormal)
Dabbled
Gothtober
Creepy Cupcakes
365 Halloween