I have just uploaded an article I wrote almost five years ago to the day. It was my first attempt and I wrote about Oracle AQ which is Oracle version of a messaging product.
AQ is included with the database and has a lot of nice features including full support for XML payloads. Another important benefit is that your messages are synchronized with your DML as both are committed in the same transaction.
You can find the article here. Please post comments and questions here.
I will post a couple more articles that I've written but somehow never got posted to this site. I will write a short blog entry about each of them to get a permanent place for comments about each article.