Problem Getting Notification On Changes from the Database

Question

Hi Experts, 

I am new in C#. I've a problem with database notifications..

I've develped a windows application in c# using web services just like little-bit  as  skype. In which i want to show that who is online/offline/absent/Lunch to all online users using notifyicon in c#

i've used the notifyicon but it doesn't show to all users because that information don't come from the database it has been defined statically.

so i want to know . how can i implement this.

i've searched on google. find some sql dependency, query notification requests, Push technology..

But i am just confused.. i don't even understand what i need to do for my application..

I need some proper guidline

Thanx in Advance.