Videomaker – Learn video production and editing, camera reviews › Forums › General › Video and Film Discussion › Free stock footage › The Prelinger Archives (ht
The Prelinger Archives (http://www.archive.org/details/prelinger)
Footage Firm (http://www.footagefirm.com/freeclips.asp)
There are more but these two have the most (especially Prelinger).
You can also find good stock footage for reasonable prices (like when Digital Juice runs a special on their VideoTraxx – I bought all three volumes for under $400 combined – over 100 DVD’s filled with RF footage).