What are the dimensions of the usable area on a Nokia N97 in portrait mode, excluding the top (signal/battery) and bottom (menu) bars?
Size: 3.5" Resolution: 640 x 360 pixels
I know this isn't the answer you are looking for, but I am unclear as to why you would need the area you are talking about since the battery bar, signal bar, and operator logo can all be in different places depending on if your device is unlocked and/or a number of other factors. Take a look at these screen shots to see for yourself:
http://phonereport.info/wp-content/uploads/Nokia-N97-S60v5-screenshot-15.jpg
http://www.n97fanatics.com/wp-content/uploads/nokia-n97_011.png
http://i40.tinypic.com/ilj9l2.jpg
http://www.allaboutsymbian.com/news/images/rda/Nokia%20N97-5.png
You will notice that in the first and second pic the battery symbol is left of the battery bar and in the third and fourth pic the battery symbol is under the battery bar. Also the size changes again if the phone is horizontal. If you still need this info you should be able to deduce what the size is base on the links to the pics I provided since they are exact screen shots. Just open them up in paint and crop the usable portion to which you refer and see what size it is. When I did it I came up with 505px high for the image with the battery under the battery bar, and 535px for the image with the battery to the left of the battery bar. Hope this helps!