I don't know what check-in is like over your side of the pond.
But the general rule of thumb here is that check-in opens about 2 hours before departure and closes about half an hour before departure. You'll have more chance of getting the seat you want the earlier you get there (unless you are able to check-in online and pre-book your chosen seat).
( JeffTheDogFucker Can you dig it?, Wed 22 Jun 2011, 18:29, 1 reply, 15 years ago)

I think you can choose your seat when you book your flight, depending on when you book it.
At least that was the impression I was given when looking at flights.
( Lisette von Falcon, Wed 22 Jun 2011, 18:31, Reply)

It's just the same your side of the pond as it is over here.
Don't worry about it. Ask people's help and it's quite easy to do.
( girlinthehole, Wed 22 Jun 2011, 18:47, Reply)