Italian bars, which serve coffee, pastries, and snacks, as well as beer and wine, are really nothing like bars in the U.S. In Italy a "bar" is a place to grab a quick bite, have coffee with a friend, read the newspaper, and socialize, perhaps with a beer. Most Italians have a particular bar that they 
frequent pretty much every day, and you will find bars everywhere you go in Italy. They are great places to eat a quick breakfast (in Italy this means a coffee and a pastry--- breakfast, colazione, is rarely anything more), have a light lunch, or afternoon snack, or simply a bracing delicious espresso when you need a break from sightseeing.
Here's what every Italian knows about bars. First, you decide what you want and PAY at the cassa (cashier), then take your scontrino (receipt) and give it to the barman. If it's especially busy, just put the scontrino where he can see it on the bar in front of you. Standing at the bar is the way to go; you will pay nearly double for the privilege of sitting down. However, if you do decide to sit and rest at a table, you can stay for as long as you like for the price of a cup of coffee.
Forget what you know about ordering coffee in a Starbucks. If you order a "latte" in Italy you will get a glass of milk, along with a funny look. Although there are many, many variations, just like here, these are some basics ways to take your coffee:
caffe espresso - a small cup of very strong coffee
caffe Americano - American-style coffe
caffe latte - hot milk mixed with espresso and served in a glass for breakfast (only)
caffe Hag or decaffeniato - decaf
caffee doppio- double espresso
caffe freddo- iced coffee
cappuccino - espresso infused with hot steamed milk and drunk in the morning
Italians never drink coffee with any meal except breakfast, although an espresso is sometimes ordered after the meal. Tea is considered a morning or between-meal beverage. One drinks wine or water with meals. Only a tourist would ever order a caffe latte or cappuccino in a restaurant after lunch or dinner. One thing for certain--the coffee you drink in Italy is likely to be the best you'll ever have. I know many people who can't bear to drink the stuff served here after they've been to Italy!
