Download the latest WinUAE beta (won't be neccessary once WinUAE 2.3 is released).
Download the filterhaders.zip from thw WinUAE website.
Copy the files from filtershaders.zip to WinUAEs data directory (on Win7 that would be C:\Users\Public\Documents\Amiga Files\WinUAE).
Important: rename the 'overlays' folder to 'masks' (most likely this won't be neccessary once WinUAE 2.3 is released).
Create a new overlays folder (most likely this won't be neccessary once WinUAE 2.3 is released).
Copy the bezel images to the new 'overlays' folder.
Open/Start WinUAE in fullscreen mode, use D3D! (Miscellaneous Page).
go the the filters page. If you've done everything correctly you should be able to select the bezel image as an overlay now.
Scale the image until it fits the bezel or use Autoscale (might not work perfectly).
Additionally play around with various filters and/or scanline masks until you find something you like.