Need help with opening a zip file on my iphone/ipad

Hi I wonder if someone knows how to open zip files on an iphone/iPad? I have tried win zip, I zip and filer but can't seem to find any option or any indication of how and where to open it. If it helps any, it is a series of MP3 audio tracks contained in a zip folder.
Any help with this is much appreciated as this is really annoying.
Cheers