I just purchased one yesterday as well - I did ask if you had to be a 'teckie' to install it - I was reassured you didn't, but I'm still a bit dubious - they did send me a link to review - it is in Chinese, but I was told to follow the pictures... here is the link
焦點工坊--PENTAX K100D 對焦屏安裝教學--
Let's hope we know what to do once we get the screen.
I really am looking forward to using it - I just purchased an A50mm f1.7 earlier this week - I've been very impressed with the photos I've been taking, but am looking forward to some assistance with focusing.
Let's keep each other posted with our progress...
Good Luck!