Did you know you can use the Dock to control many active applications? For example, if iTunes is active, you can control it from the Dock to skip, repeat, shuffle and mute songs and music. In Safari, you can open a new window or jump between different tabs and windows directly from the Dock. In Mail, you can jump between open emails, create a new blank email, and (in Leopard) create a new To Do item directly from the Dock. I use this feature all the time.
To do this, all you have to do is click and hold down on any open application’s icon in the Dock. After a second of so, a menu will pop up with various options specific to that application.
One of the Dock-based commands for any application is “Open at Login.” If you choose this option, the selected application will automatically launch every time you power on your Mac. For example, I need to use Mail, Safari, Small Dog’s custom database and iChat right away every day at work. I’ve selected all of these apps to “Open at Login.” Monday to Friday, I simply turn on my Mac, enter my password, and then leave to get some coffee. When I return, the machine is ready to go!
Note that if you decide you no longer need an application to launch at login, simply go back to the Dock and de-select “Open at Login.”