Many iPhone applications present a brief 'splash screen' when starting up. Here's how to make one.
Create a PNG image named 'Default.png'. It must be exactly that filename, case sensitive. Put this in your Resources folder of the project. The application will display this image briefly when the application first loads.
Technically this image isn't supposed to be used as a splash screen. It is supposed to be a image which resembles the running UI of your application. It's purpose is to make the application show something while it is starting up. By doing this, it doesn't look like the application has frozen while starting up. Despite this, most people just use this feature as a splash screen.