Please note before ordering: there are at least two different models of screen for the Kindle 3 keyboard.
ED060SCE(LF)T1-0I and ED060SC7(LF)C1 (you can find the model no. on a sticker on the back of the screen). My UK 3G model had the ...C1 built in. Be sure to order the correct one. The ...T1 screen will work as a replacement for the ...C1 model, but badly (text is fine, images and screensavers are not display correctly).
I just broke a brand-new screen by trying to get the speaker grills in. Pushed it down onto a flat surface ... the screen then broke in the bottom. I still haven't managed to get the speaker grills in. Be very, very careful if you try this.