Ok, here is a beta Global 40 iWork Numbers spreadsheet for tracking IPCs. It works on Mac OS X, iOS, and PCs via iCloud in a browser. It is NOT Microsoft Excel compatible (and don’t ask me to make an Excel version, I don’t have time).
My group uses a projector to put the spreadsheet on the wall so everyone can see it. It also looks good on a 60 inch TV at 125% (with the Formatting pane hidden), but it does require vertical scrolling (sorry, but there’s just too many territories to fit all of them on a 1920x1080 screen).
EVERY territory has a popup menu. Just select who owns the territory, and the IPC income table will update accordingly. When someone declares their combat moves, mark the territories as Contested, and then update them after the battles have been fought. Contested territories are highlighted in red, so marking them before battle will help you keep track of which territories need to be updated after battle. (NOTE: Marking a territory as Contested removes its IPCs from the country that owns it. The IPC totals will be accurate after combat is concluded and the territory is assigned its rightful owner.) There’s also a National Objectives table that is mostly automatic, but it does have some checkboxes for certain situations. And, if strict neutrals become pro-whoever, there are popup menus to set them accordingly (which should be done because it affects a NO for Germany).
The spreadsheet is editable via iCloud in a browser, but there are limitations. You can perform minor edits to equations, but you’ll need Numbers on a Mac to edit equations with references to other tables. Also, there is a hidden table that deals with victory cities. If you accidentally select it and edit a cell, you’ll screw up the Victory Cities table (the one with the totals).
So, have a look and let me know what’s broken. The spreadsheet is based on one I did for Spring 1942 (which was play tested many times), but I haven’t had a chance to use this version in a game yet. Everything looks good to me in my limited testing, but the logic for the National Objectives is somewhat complicated, so pay close attention.
Edit: Attached a pict of a Spring 1942 game where we used a similar spreadsheet.
Edit (8/13/2015): Removed the spreadsheet for and added an updated version to a new post.