Pop up or iFrame like facebook in c# asp .net

See more:

C#

ASP

Ajax

Facebook-API

here i go, i am trying to create a reminder/scheduler in asp page, but the display theme of a reminder, (set on /off) i want, is similar like facebook.
As in facebook we click an image and it loads in the same page like a pop up, leaving the main page inactive while we perform actions on popup.

When my reminder goes off/on, i want a ballon on the lower-right corner, Like messaging in facebook.

I have also noticed the same pop-up windows on wallpaper sites etc.

i need any tutorial, links, hints, whatever you can tell,

thanks in advance.