Q: To be more specific, when I take a look at buying tickets online, prices only come in Euro's, and I'm rather unexpirenced at international travel/purchasing on the net.
A: BigSexi is right - when you use your credit card, they (MC / VISA) will bill you at the exact dollar/euro rate for that day. There may be a small charge for this in addition (I pay 0,03% of the total in other currencies, i.e. $100 charge= $.30 extra).