Splitting Excel 2007 in task bar

"Launch Excel twice (quickest way is pressing the Windows logo and typing Excel)

Open each Excel file in a seperate instance of Excel, you can now order them side by side if you like or move them to another monitor.

To get them side by side nicely, press Windows + Left/Right arrow to have it stick to either half of the screen."

"I much prefer to keep the files in the same instance of excel. There are a number of features that don't work between files if you open in different instances (as in Ivo's answer). Another way to accomplish this is to open the 2 files in the same excel window, then go to View > Arrange All, then select Vertical and press OK. Same excel window, but can now view 2 files at once.

You can even view 2 sheets of the same file this way. The only difference is that first you must select View > New Window.

There are times where I use Ivo's method. Mainly when I have files with macros that I need to test or compare to other versions. I find it best to separate the instances and processes."