I was recently looking for some stock footage to put behind my friend who was playing guitar infront of a green screen for a musical appeal. This lead me to a very nice website with completely free stock footage! It’s high quality SD and also some HD videos, royalty free and split into categories so it’s easy to find what you want.
It’s not the biggest collection of stock footage out there, in fact it’s kinda small, but it’s the best free site I’ve found so far. They might not have exactly what you are looking for but if they do then it’s perfectly set up to deliver.
The site is owned and operated by Footage Firm who sell royalty free stock footage.
Check it out at: www.stockfootageforfree.com
And check out the video I made with the use of some free stock footage here.
So thanks to Footage Firm for the free footage! 
Great site, thanks dude! – I’ll use it myself, and have also added it to eh resources page on http://www.motionshare.com.
There is also a new website offering hundreds of full resolution HD (1920×1080) stock footage clips for free: http://www.xstockvideo.com
Just go to the site and download to your heart’s content. All of the free footage on the site comes with a royalty free license granting full use in all types of projects.
Enjoy!