Pokemon X&Y will read your registered friends list from the 3DS system, so the game will automatically have those people as your friends.
Some areas have different types of methods of getting around. (i.e. we've seen the grinding and so on). Depends on area.
Flow of battles - seeing opponent's team ahead of time - is the same as before. You can select the song for the battle though.
Serebii Updates: Can select music before a battle http://www.serebii.net/index2.shtml
Bike is confirmed to return
Q: Riding Pokemon - benefits? Diff from bike? A: Sounds like you can 'borrow' Pokemon to traverse to destinations. Can help open paths too.