I have several apps that I have configured to open upon login (mail, calendar, skype). The problem is that I have to close their windows every time I power up the system so that they are running but have no open windows. Is there a way to configure them to start without open windows?
In the Accounts preference panel (system preferences), select your account and click the 'Login Items' tab and check the box to 'Hide' the selected application. That should open the application in the background.