Now i do an own instructable about the screen of my homecinema.
Its pretty cheap and after the final cleaning it looks great.
Step 1: The Blueprint and Measurement
at first i started my beamer and take a look on the pictruresize i like and do some little marks wit a pen on the wall.
then i do a little sketch about how i would like to have the look of the thing done, and scratch the right measurement on the wall.