Yeah, basically what Cannonaire said.


The whole idea is to make two files (with different quality resolutions and/or codecs),
then trick your editor into using whatever file it see's in the file location of your footage.
As long as they look the same frame-by-frame, and have the same name and file extension (like .avi), your editor cannot distinguish between the two files.
You could do it the long way in your timeline, or
1. Close your editor.
2. Switch the file location of your footage with the Real/Proxy file.
3. Re-open your editor, and hope it uses the swapped file in your timeline instead.
4. Edit with the Proxy file. Render with the Real file.
Tips:
-Make sure your Proxy file has the same framerate as your Real file.
-Repeat this process as you edit, so you know it is working, ensuring all your frames line up. (You really don't want to botch your whole project...)
-You may need to change your project framesize to match the new file.
-Use something like UTVideo for your Real file, and optionally a different codec for your Proxy (maybe ffdshow's MJPEG...)
-Play with resolution/quality of your proxy file. I've gone as low as 320x180, and it was lightning fast (quality was iffy but good enough for me...)
-If you know a bit of Batch, you can write a script to automate the whole process.
The nicest thing about proxy editing, is you can use the slowest computer ever, and it'll still be fast in your timeline, assuming you aren't applying any effects that require processing power.
(until it comes to rendering... but I usually render on a different computer at home anyway... )
Hope this helps.
~Phan