"Rock Band’s unprecedented offering of over 70 songs to date currently available for purchase and download in the US will be made available in Europe beginning on Tuesday, May 27th. Each track will be available for 160 Microsoft Points on Xbox 360. Following that date, all new Rock Band Downloadable Content will be available simultaneously in the US and Europe on a weekly basis. For a complete list of Rock Band songs available for purchase to date, please go to http://www.rockband.com/dlc."
From the horses mouth, so to speak.
Source
EDIT: According to a guy over at the official forums who won an IGN competition, the European drums have rubber on the pads, but I will wait and see.
How much is 160 points?
Songs are $1.99 on the PSN.