Is it possible to see how many people in the world have Bitcoins?

[gabrielle]

is it listed in the system somewhere?

how many ppl in the world do you think own Bitcoins? 10,000? 100,000?

[dazoe]

Buy looking at the number of bitcoin clients connected to the IRC channel you'd get a rough estimate.

[Stardust]

Buy looking at the number of bitcoin clients connected to the IRC channel you'd get a rough estimate.

Not quite, some may use MyBitcoin, etc, or store their bitcoins offline.  But you may always check the blockchain to see which addresses hold the most coins...

[Maged]

There are currently 18,491 bitcoin nodes running. For more interesting stats, see this post:
http://forum.bitcoin.org/?topic=2346.0

[bitcoinspot.nl]

Try this one:

this file should give you alle the known nodes, up and down, on the internet.

Greetz.