Another 5 minutes with C# to post to Google Blogs (Blogger.com) using Google Blogs SDK

// Create service to be used for queries              Service service = new Service ( "blogger" , "blogger-sample" );              AtomEntry createdEntry = new AtomEntry ();              // Create credentials you should add your blog username              // and password here             service.Credentials = new GDataCredentials ( "your_username" , "your_password" );              // As I only have one blog to speed up - I am taking it,              // You can extend here in order to allow the user to              // select from mutliple

blogs if he / she has.
             Uri firstBlogUri = GetFirstBlogUri(service);
            
             // If we have the Uri - it's time to actually post.
             if (firstBlogUri != null )
            {
                // Create FeedQuery and assign Uri.
                FeedQuery query = new FeedQuery ();
                query.Uri = firstBlogUri;

                // Create Atom Feed from that query.
                AtomFeed feed = service.Query(query);

                // Create atom entry for the new post
                AtomEntry newPost = new AtomEntry ();

                // Fill in the post information
                // You need to have a control named richTextBox2 which will
                // contain the post body and a textBox1 control which will
                // contain the post title.

                newPost.Title.Text = this .textBox1.Text;
                newPost.Content = new AtomContent ();
                newPost.Content.Content = richTextBox2.Text;
                newPost.Content.Type = "html" ;
                newPost.Authors.Add( new AtomPerson ());
                newPost.Authors[0].Name = "Pavel Donchev" ;

                // Try to publish and report success / fail:
                try
                {
                   createdEntry = service.Insert(query.Uri, newPost);
                }
                catch ( Exception ex)
                {
                   MessageBox .Show(ex.Message);
                }
                if (createdEntry != null )
                {
                   MessageBox .Show(newPost.Title.Text + " posted successfully!" );
                }
            }

There is also a helper function to retrieve the blog Uri:

       Uri GetFirstBlogUri( Service service)
       {
             FeedQuery query = new FeedQuery ();
             // Retrieving a list of blogs
            query.Uri = new Uri ( "http://www.blogger.com/feeds/default/blogs" );

             AtomFeed feed = null ;
            feed = service.Query(query);
             AtomEntry entry = feed.Entries[0];
             for ( int i = 0; i < entry.Links.Count; i++)
            {
                if (entry.Links[i].Rel.Equals( "http://schemas.google.com/g/2005#post" ))
                {
                   return new Uri (entry.Links[i].HRef.ToString());
                }
            }
             return null ;
       }