Alex, the screens on the Orbit and Orbit 2 are totally different. The former is the standard recessed screen, but the latter has the new flush screen, so the protector needs to be much bigger to cover the whole thing- the smaller one would start getting snagged and frayed quite quickly.
As Wavey says, O2 provide a fairly good one in the box- it is a bit shiny and gathers grease quickly, but good enough till Proporta release one
For applications, look in our threads around the site, particularly
What Apps do the Moderators Use .