How to make pop-up alert which is like MSN when friends get online

I would like to know how to make pop-up alert which is like MSN when friends get online. The pop-up alert will fade in the right-bottom of the w开发者_如何学运维indow and will fade out after 3 seconds.

I am using C# (VS2005). Please kindly advice me if any tech tools i should apply or any method to do. many thanks!!:)

In GWT (java-based web framework), you can use gwt-comet.

I think you can integrate it with any server (IIS and .net) scince, GWT is a user-interface framework