http://www.youtube.com/watch?v=uJuGxYnNxcM
You probably remember these guys, had a lot of success in the 60′s and early 70′s; pretty fair musicians and song writers too.
At this point, the rooftop was the probably the only,safest, place for them to perform a live, free concert.
They do rock.
From beatlesbible.com:
The 42-minute show was recorded onto two eight-track machines in the basement of Apple, by George Martin, engineer Glyn Johns and tape operator Alan Parsons. The tracks were filled with the following: Paul McCartney, vocals; John Lennon’s and George Harrison’s vocals; Billy Preston’s organ; McCartney’s bass guitar; a sync track for the film crew; Starr’s drums; Lennon’s guitar; Harrison’s guitar.
‘That was one of the greatest and most exciting days of my life. To see The Beatles playing together and getting an instant feedback from the people around them, five cameras on the roof, cameras across the road, in the road, it was just unbelievable.’
Alan Parsons

i was hoping for this!
and, the really beautiful, soulful,keyboard sound from Brother Billy Preston.
“5th” Beatle as they say..
probably,
but quite a bit more than that.
as an addition to the post is these words on the details , from the band and those involved.
a really cool deal.
http://www.beatlesbible.com/1969/01/30/the-beatles-rooftop-concert-apple-building/