Progress Bar: unknown task length, how produce "bouncing" animation

How do we produce a progress bar with the kind of appearance found in the one present during Windows XP startup? That is - the contents of the progress bar "bounces" back and forth until the task ends. It does not give feedback on "time left" or "items covered". We have several tasks with unknown lentgh in an application. For such tasks, we want to present active feedback to the user. We need the progress bar to work in both Windows 2000 and Windows XP look. Regards, me

Check out the ActivityBar sample on GotDotNet. http://www.gotdotnet.com/userarea/keywordsrch.aspx?keyword=Activity%20Bar