I did it about thirty years ago (twice!!) and it's definitely a diy job - if you follow the instructions to the letter.
Don't think of it as hanging wallpaper. It's more like hanging linoleum. You can't trim it round switches and sockets and door-frames in the same way as you would with paper: you really need to do all the cutting before you soak it and hang it - which is really the only tricky bit.
