I want to make an application that works like this: On entering a view in the program the application will begin downloading some data from the internet. This happens in the background. However, since the data to be downloaded may require some waiting, I want to provide the user the ability to leave this section of the application. So, what I need is a way to stop the downloading of data from the network after the download has began. Is there any class I can use for that? Right now I am using the NSURL class with "initWithContentsOfURL" method to obtain the data from the internet. Any ideas?