Per Kevin's comment, the simple fact is that although Dumbledore is known to have worked *with* Nicholas Flamel, there's [no canon mention][1] of Dumbledore working on the Philosopher's Stone;

> "Professor Dumbledore is particularly famous for his defeat of the
> dark wizard Grindelwald in 1945, for the discovery of the twelve uses
> of dragon’s blood and **his work on alchemy with his partner, Nicolas
> Flamel**."

Although Flamel is known to be the only contemporary possessor of a quantity of the Stone, there are no reasons to assume that Dumbledore had any hand in creating the current (or past) batches.


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As to whether Dumbledore has been using the Stone/[Elixir of Life][2], there's a [quote from JKR][3] to indicate that while he's very old, there's no indication that his age is unnatural. On top of that, his brother is very much alive (and appears to be much the same age) which wouldn't be the case if his life had been extended artifically.

> "**Interviewer** : *How old is Prof. Dumbledore...*
> 
> **JKR:** *Dumbledore's about 150 years old... Wizards have a longer life expectancy than us Muggles...*

  [1]: http://en.wikibooks.org/wiki/Muggles%27_Guide_to_Harry_Potter/Books/Philosopher%27s_Stone/Chapter_13
  [2]: http://harrypotter.wikia.com/wiki/Elixir_of_Life
  [3]: http://www.accio-quote.org/articles/2001/0301-bbc-rednose.htm
  [4]: https://i.sstatic.net/746bz.jpg