I subscribed to just a couple select real (not web-based) magazines and one of my favorite is iPhone Life. FYI, this used to be the Smartphone and Pocket PC magazine that has since transitioned into this iPhone version. I have contributed articles in the past and in the current issue you will find my article on the two premier Office applications, Documents To Go and QuickOffice. You can get actually get this issue now for free if you want to check it out. They are also available in bookstores and retail shopping stores around the country.
I wrote more detailed reviews of both Dataviz's Documents To Go and QuickOffice here on this blog and my iPhone Life article summarizes those, along with discussing the latest updates to both applications. These two applications are regularly updated with an Excel update coming soon to Documents To Go and this is a great thing for iPhone owners since it helps give us better applications that serve our mobile Office needs.