digital juice and footage

digital juice and footage firm are a good place to start.

If you have After Effects or Motion there are some decent backgrounds included…or you can just make your own with these programs…

AE has a brainstorm feature where you can make a simple background and it willcreate unlimited backgroundsbased on specific features you select from that background.

http://stockfootageforfree.com/

http://www.footagefirm.com

http://www.digitaljuice.com

http://library.creativecow.net/articles/rabinowitz_aharon/Brain_Storm.php (AE brainstorm reference)