You need to find the resolution of your device and then set that resolution (or closest to it, in the editor. You can approximate the size of the phone by moving gui elements till they fit on your phone, then re-size the editor window for your game view till the gui elements are in view. You should only have to do this if unity doesnt list your dimensions of your screen. Also remember that textures may also shrink/grow based on pixel density, so export your images at a certain pixel density to get a good approximation in unity of the size before it runs on the device and is not correctly sized.

You can change the editor window size to a preset by going to the game window tab and in the upper left is a drop box that has listed screen sizes to mimic. I currently cant get 1280x800 (galaxy tab 10.1) to show correctly in the preview window, i can only get it in free aspect, and only match the 1280 width.

Hope this helps. Not to hijack, but itd be great to find a way to resize my height to match 800. If anybody knows thatd be great! :)

May sound silly but have you actually designed the game in the correct resolution for the GS2? 480x800 if i remember correctly.