I think Linq is your friend:

// Easy to sort using Linq
            var blogs = MethodThatGetsBlogCollection();
            var sortedBlogs = blogs.OrderBy(b => b.Header);

            // If you cant use the IEnumerable sortedBlogs but need a BlogCollection, you have to loop...:
            var sortedBlogCollection = new BlogCollection();
            foreach (var blog in sortedBlogs)
            {
                sortedBlogCollection.Add(blog);
            }

The Linq-expression did the trick. I have to study linq more, seems that it solves alot of problems. Thanks!

/Peter