I'm feeling optimistic, how much would you say it would cost to travel from Ireland to South Africa in 2010?

Ideally I’d like to see 2 matches but realistically how much would they cost and how early in advance would you have to book. Also how would you go about booking tickets?

Finally are 2nd round & quarterfinal matches (and even dare I dream semi final & final matches) much more expensive than 1st round ones?

it's a costy trip, you need to consider match tickets, plane tickets, hotel and food as part of your savings if you're willing to go...
http://www.fifa.com/worldcup/organisation/ticketing/pricesandmatches.html
the link above is the tickets and their prices according to seatings, the first phase of ticketing is open until the 31st of this month, if the number of those who applied are more than the seats available then they will be drawn randomly, doesn't matter if you apply now or on the alst day, but i read that over 500,000 applied online, not including those who applied by mail or fax, or even those who applied from within South Africa.
the 2nd phase starts in a month or 2, in that phase it will be a first-comes-first phase, so if you apply first you have a priority than those who apply after you, but this only applies if there are any available.

back to the planning, plane tickets are something like $1,200-$1600 round trip for 1 person, let's say you get basic tickets of seats behind the goal (this depends on which matches you watch, you calculate this part from the link i provided), and you might need let's say $120 per day which includes your hotel stay and food, and you do the math :)

I went to see the WC semi/final (Italy vs Germany) and the Final (Italy vs France) in 2006 in Germany and it was worth ALL the money I spent on it. I sold a 50" LCD TV in order to buy the tickets and saved up for months and months working longer hours for the plane, hotel and food money. It's expensive, but there are probably two single moments that will ever beat those evenings: the day i get married to Rapture and the day I become a father.

Go for it. Do it do it

a bizzilion trillian euro :p
no i dunno id say a lot, but go for it itll be well worth it :)