Viper’s Video Quicktags, a plugin for WordPress that lets you embed videos in your posts.

From the site:

This Plugins Provides Support For:

• YouTube
• Google Video
• IFILM
• Metacafe
• MySpace videos
• QuickTime files
• Generic video files (AVI, MPEG, WMV, etc.)
• FLV (Flash video) files (only basic support, use a dedicated FLV plugin if you want full configuration options)

It, also, helps to bypass having to get an API from wordpress.com to post youtube videos.

Thanks Viper.