I always wondered, how many Awards we have in our country and what is the difference between those, which is higher in hierarchy. Learnt about that in Wikipedia (This is one site, which I have started going through for anything and everything and I am never let down because it gives so much of details :-) )

Padma Shri
This award is given by the Government of India generally to Indian citizens to recognize their distinguished contribution in various spheres of activity including the Arts, Education, Industry, Literature, Science, Sports, Social Service and public life. (Padma = Lotus, in Sanskrit). As of 2008 Feb, 2095 people have received the award.

Padma Bhushan
This is awarded to recognize distinguished service of a high order to the nation, in any field. It stands third in the hierarchy of civilian awards, after the Bharat Ratna and the Padma Vibhushan, but comes before the Padma Sri. As of 2008 Feb, 1003 people have received the award.

Padma Vibhushan
The Padma Vibhushan is India’s second highest civilian honour. It consists of a medal and a citation and is awarded by the President of India.

It was established on January 2, 1954. It follows the Bharat Ratna and precedes the Padma Bhushan. It is awarded to recognize exceptional and distinguished service to the nation in any field, including government service.
As of Feb 2008, 235 people have received the award.

Bharat Ratna
Bharat Ratna (translates to Jewel of India or Gem of India in English) is India’s highest civilian award, awarded for the highest degrees of national service. This service includes artistic, literary, and scientific achievements, as well as “recognition of public service of the highest order.” The award was established by the first President of India, Rajendra Prasad, on January 2, 1954. The honour has been awarded to forty persons, a list which includes two non-Indians and a naturalized Indian citizen. Tamil Nadu and Uttar Pradesh are the states with the most number of awardees (8 each). The actual award is designed in the shape of a peepul leaf and carries the Hindi-written words “Bharat Ratna” on the front. The reverse side of the medal carries the state emblem and motto. The original statutes of January 1954 did not make allowance for posthumous awards (and this perhaps explains why the decoration was never awarded to Mahatma Gandhi), though this provision was added in the January 1955 statute. Subsequently, there have been ten posthumous awards, including the award to Subhash Chandra Bose in 1992, which was later withdrawn due to a legal technicality, the only case of an award being withdrawn.

While there was no formal provision that recipients of the Bharat Ratna should be Indian citizens, this seems to have been the general assumption. There has been one award to a naturalized Indian citizen — Agnes Gonxha Bojaxhiu, better known as Mother Teresa (1980); and two to non-Indians — Khan Abdul Ghaffar Khan (1987) and Nelson Mandela (1990).

No one has been conferred with Bharat Ratna since 2001.