class/lib for parallel downloads on iphone

I need some class or lib that would allow me to run multiple parallel downloads. I didn't have luck finding any, do you guys kn开发者_开发知识库ow about something useful? I need to add new files to download dynamically, so something that only get initialized with urls at the beginning won't help me much.

I tried to create my own, but I had some problems with it. So I figured I would try to get something that is already done.

Have a look at the similar question and at this blog entry which contains sample code that uses NSURLConnection subclass.