flush question

[rjc199]

Given:
1) you have two suited cards, jack high (for instance spades)
2) the flop is spade - spade - other, the turn is not a spade
3) the river brings another spade to complete my flush
Question:
1) What is the probablility of another player in a 10 handed game also having two spades?
2) What is the probability of another player in a 10 handed game having a higher flush than you? Exclude straight flush possibilities because they are impossible with the board we are concerned with.
3) In general having an X high flush where X is trey through ace, what is the probability of another player beating you with a higher flush (obviously if somebody else has a flush your three high flush is never going to win)? Also exclude straight flush possibilities here.

Is the answer simply the probability of somebody being dealt spade cards (or in the 2nd question suited spades Q, K, or A high), or does the fact that the board shows three spades, and the fact that you have two spades alter the probability of there being spades in people's hands?