http://oscars.org is a great source for the history of the Academy Awards.
Some facts and figures :
1929; The first Oscars were given at a banquet at the Roosevelt hotel in Los Angeles, with 270 attendees. Recipients were announced three months earlier.
The next year the results were kept secret but an advance list was given to newspapers for publication after 11pm on the evening of the awards. This continued until 1940 when the L.A.Times published the winners in its evening edition – readily available to arriving guests.
The sealed envelope system came in after that!
1935: Oscars for Film Editing, Music Scoring and Best Song were inaugurated.
1937: For the first time, there was a Best Supporting Performance Oscar. (Walter Brennan and Gale Sondergaard).
LUISE RAINER was the first to win two Oscars (THE GOOD EARTH,THE GREAT ZIEGFELD).
WALTER BRENNAN was the first (and only) performer to win three Oscars for acting in the Supporting category – COME AND GET IT (1936), KENTUCKY (1938) and THE WESTERNER (1940 )
1939; The first Oscar for Special effects was given for THE RAINS CAME.
1944; Winners in the Best Supporting actor/actress category were given full size statuettes instead of plaques.
1944: For the first time, the Oscar Ceremony is held at Grauman’s Chinese Theatre.
1947: The general public were allowed to buy tickets for the Academy awards.
In 1949, ROBERT MONTGOMERY was Master of Ceremonies, and the Costume Design Oscar was introduced. (winners were JOAN OF ARC and HAMLET).
1953: TV cameras covered the event and had the largest single audience in TV’s 5 year commercial history.
FROM HERE TO ETERNITY,in 1954, was the first film to tie with GONE WITH THE WIND for a record 8 Oscars.
In 1955, Garbo was given an Honorary Award for her “unforgettable screen performances”.
The 1956 Oscars was GRACE KELLY’s last public appearance before her marriage to Prince Rainier. (Her Oscar was for THE COUNTRY GIRL in 1955.)
1961; WENDELL COREY was Academy President till 1963.
1969: The first worldwide TV broadcast.