Since WordPress 2.9 there has been a super easy way to embed a YouTube video in your WordPress site – simply paste the YouTube URL directly into your web page.
The same approach works for a wide variety of other shareable content:
- YouTube
- Vimeo
- DailyMotion
- blip.tv
- Flickr (both videos and images)
- Viddler
- Hulu
- Qik
- Revision3
- Scribd
- Photobucket
- PollDaddy
- Google Video
- WordPress.tv (only VideoPress-type videos for the time being)
- SmugMug
- FunnyOrDie.com
Reference: WordPress Codex