I am currently working on CiWiki alias DidiWiki to make it able to show embedded video, such as youtube, dailymotion, vimeo, veoh.
The first trials work pretty well. Currently, it works with youtube, dailymotion, vimeo and veoh.
The syntax is easy for youtube in particularly, just type in the beginning of a new line:
For instance, this youtube=http://www.youtube.com/v/UU4Ly2UMMpc will show the video of Lady Gaga Let's dance.
I have to test a little bit more before releasing the new version of CiWiki DidiWiki 1.0