Embedly is a wonderful wordpress plugin (there is also a jQuery version available) to embed almost everything (Ok. not everything but the ones you wish to embed.) easily into your wordpress posts and pages. With the help of this plugin you just have to paste a URL and it will display the content in your post properly. For example, if you paste a youtube.com URL it will display the video.
Currently Embedly supports 160 services. The implementation of the plugin is very simple. All you have to do is upload the plugin to wp-content/plugins folder and activate it.
There is an option panel where you can select or deselect the service.