One of the limits imposed upon you with iPhone applications is that your application must run in the foreground. When the application is closed it will exit.
The only way around this is to provide a service on your website or something, effectively moving the application from the phone to another location while it is closed, and pushing notifications to the phone in the form of badges. This is very severe limitation for most applications, but it works quite well for others =)
与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…