I just put up some freebie Halloween images on Freebies.
If you want some Blogger backgrounds, they're on Blog-ology and headers are on Extras. All the instructions for installation are there as well.
If you'd like to see how the backgrounds look in Real Life:
- 2-column Fright Night is on BladeRubberStamps Blog
- 3-column Fright Night is on Freebies
- 3-column Horror Show is on Computery