Scheduling a post is useful at certain time especially when you are going out for a long holiday, as it keeps your blog automatically updated, so your readers won't know you aren't at home.
Scheduling a post is simpler done than said, just type a new article, and in the 'Post Option' below the editor, type in the post's date and time. If you enter tomorrow or a few days later, Blogger will postpone the posting of the article until the specified time comes.
You can also use this date and time technique to order your post. See this tip: http://blogger-newbies.blogspot.com/2008/12/ordering-posts.html.