iZip is the easiest way to view ZIP, ZIPX, RAR and 7ZIP files on your iOS device. Best of all it's completely free so you can access your files (even WinZip password protected versions) without limitations!
Note: while the app is called iZip.com, it isn't a web service. Your files are processed locally on your iPhone or iPad. For more information about iZip please visit www.izip.com