This means that a very small sub-set of PS3 owners in PAL territories will discover that their HDTVs only display the game in 480p.
The reason for this is that some older HDTVs don't support 720p resolution, which is the game's highest available, and despite the developer's ability to upscale that 720p image to 1080i that does require a bit of extra programming to achieve.
Fortunately not many people in Europe will suffer on account of it, because most of our HDTVs are more up to date. In the US, however, the problem is much more prevalent, which is presumably why - alerted to it at the last minute - Naughty Dog acted quickly to satisfy its customers there.
In the end then, we got Uncharted on 7th December with 480p and 720p support, but not 1080i.