This, if you remember, is an updated version of the Galaxy S, and features a better processor, larger battery, and runs Android 2.3 Gingerbread from the start. The Galaxy S Plus has a 1.4 GHz processor (the original only has 1 GHz), and a 1650 mAh battery (as opposed to 1500 mAh).
Today, Fonehome has learned from Samsung that this device will also become available in the UK later this year. Unfortunately, a more exact timeline has not been given. Nor any information whatsoever about pricing. It stands to reason though that this smartphone would be Samsung's upper-midrange offering for 2011, being positioned slightly below the Galaxy S II in the manufacturer's portfolio, and should be priced accordingly.
source: Unwired View