I will be traveling to Italy the end of April for 2 weeks. My travel buddy is saying to order train tickets before we leave and received an email from RailEurope to do so. Should I order tickets from RailEurope before I leave for Italy or wait until I get there? Will it be cheaper to do it this way because of the euro exchange rate?
Point-to-point tickets from RailEurope will be more expensive (probably about $15 per ticket, plus shipping) than the counter price in Italy. Most experienced travelers just get their tickets in Italy, usually just before travel time. If you are really paranoid, you can get all of your tickets at a station the day you arrive.
The only reason to get tickets for any country from here, IMO, is if it allows you to get significantly discounted tickets, and RailEurope doesn't sell those tickets.
I'd temper Lee's answer a little. Italy is one place where trains do often sell out -- especially key routes at prime travel times (like first thing in the morning, or the first train after 5pm -- especially arriving or departing Rome/Florence/Venice/Milan).
Where a certain rail segment would drastically impact your overall trip, where the train you are looking at is the first of the day, the 5pm-ish express, or the last of the day, or where you are selecting the fastest train of the day, definitely pay the premium to book in advance. Don't let $15 or $30 be what derails your plans.
Never buy rail tickets from Rail Europe. They mark up the fares quit a bit; you'll be overpaying. The official Italian rail site (http://www.trenitalia.com)doesn't accept US credit cards, but you won't have any problems purchasing ticket once you arrive in Italy.
http://www.roninrome.com/%20transportation/buying-a-train-ticket
I'd give Trenitalia's website a shot. Try all your credit cards. Mine worked last year while members of this list were stating that the site wasn't taking US Cards. They do - but they reject quite a few.
If that doesn't work, and you're set in your travel dates, go to the nearest train station when you arrive in Italy and buy all your tickets at once. You'll be able to purchase discounted tickets (at least from the machines, if not the counter) just like you would on the web, if they're still available.
If you DO try Trenitalia, register first. Wait for your confirmation to arrive by e-mail, then log back on as soon as possible to change the password to something you can remember. THEN try booking with your credit card.....let us know if it works!