I found dimensions of 107 x 70px on some support sites. However when I upload an image this size it appears cropped and squashed in the frame.
Does anybody know the dimensions or how to stop it from cropping?
If you look at the source code it says 111x74, but that also resizes your image.
It seems Facebook has not updated this yet (will probably do so on the 30th when they force everyone to use Timeline for Pages).
If you would like to make your icon the full size today... You have to manually do it from each page.
To do this: click on the down arrow near the tabs on your timeline enabled page. Then click on the pencil icon next to the icon you want to change to full size. Then it will load up a new page that allows you to upload the 111x74px icon. Then your icon will appear full-size.