Couldn't find much info on these when I did searches. I ordered a 10 pack of WriteRight by Fellowes (from amazon), CRC90002; about $8.50 with free shipping.
http://www.amazon.com/Fellowes-WriteRight-Universal-Screen-Protector/dp/B0016898TEI've been happy with them. They are not permanent, so they can be replaced. Pretty easy to apply. It takes a bit of practice/skill to apply with no bubbles. I sort of roll it on, flattening it back and forth as I go. I unpeal the backing as I go. If I see any trapped air, I pull it off a bit to get rid of it. It's important to get the air out as you go, because it does not force out very well. And it's important not to touch the backside.
The sooner you start using them on a new device, the better they work. Scratches tend to trap air, etc. But they work well even on my 4 year old Lumix. I covered my new m10 before I even put batteries in.
I'm putting it on all my displays/faces. At first I thought the 10 pack was too many, but I'm glad I got it. I understand the more permanent films are better for touchscreen devices.