I've been looking at trying it myself, but is it really necessary to play Uncharted 1 first to know the full story?
I've always liked knowing the full story (of books, movies, games) but having been out of serious PS gaming for a few years I've missed a lot of titles that are now on their fourth or higher installment, like Tekken, Devil May Cry and Metal Gear Solid (MGS 2 was such contrived crap I never bothered with 3).