Embedding Vimeo in WordPress post or page without a plugin
is fairly simple as soon as you know how. This should not only work for Vimeo but for all videos that WordPress can automatically embed like YouTube, etc. Go to your blogs dashboard > Settings > Media and tick the Auto-Embed box.
Embedding Vimeo Videos
WordPress can automatically embed Vimeo videos centered but it is important that you enter this code not in the visual editor but the HTML mode or else WordPress will strip the necessary information from your post.