There are hundreds if not thousands of examples of Scottish Country Dancing on YouTube.
The Box Hill & District Scottish Society suggest the following YouTube examples provide a good introduction to Scottish Country Dancing
This is a 6 minute instructional video which has been produced by the National Health Service in the UK. It features a group from the Royal Society of Scottish Country Dancing in Scotland and is really an introduction to SCD and it extols the health benefits which come from SCD.
Here you will find short videos demonstrating formations such as rights and lefts, hands round and back, grand chain, reels of 3, reels of 4, ladies chain and many more.
Here you can see ordinary folk attending a Scottish Country Dance class and hear them tell you why they dance.
This is a well filmed and danced example of a wonderful Scottish dance,the Eightsome Reel
This is an example of a semi professional group of Scottish dancers performing in a dancing competition
This is a group of Russians in beautiful ball gowns dancing a Strathspey
This site has links to YouTube videos of a number of traditional Scottish Country Dances. It is a good place to start if you are looking for a demonstration of a particular dance.
This is a link to a step-by-step guide to some popular dances