The train, Pompeii

Just did this trip today (July 2011). Couple of things to know. Purchase a 24 hr ticket for €6.30 (per person) at the Circumversuvian counter at Napoli Centrale. This will take you all along the Sorrento line with the stops at Herculean and Pompei and everywhere in between. It is valid for 24 hours so is good value. When leaving Naples, DO NOT TAKE THE 'Sarno' train as this looks like it heads in the same direction as the Sorrento one but it doesn't. Take the 'Sorrento' train. If you get the wrong train, you can change at Bara to get back on track, but be sure to ask the info desk which platform to be on, otherwise you'll be waiting ages like we did!!!
The Herculean stop off point is called Ercolano. When you get there, head right briefly (about 15 meters) then left down the main street. The ruins are about 500m away. You can take the mini van service from the train station for €3 if you want.
We spent about 2 - 3 hours at the ruins.
We enjoyed Herculean more than Pompei as alot of the Pompei ruins were cordoned off and it is a huge site.
The rest is easy and well documented. I strongly recommend heading to Sorrento for gorgeous Sunset - great way to end the day. Check out Lonely Planet Italy - it was our bible with maps and suggestions for the whole day.
Unless you absolutely love archeology, this was a good day trip and we weren't pushed from time.
Enjoy!!

I can't remember the cost of the ticket, but I remember the price was very reasonable for a round trip ticket to and from Pompeii Scavi. I left from the main train / bus station in downtown Naples. I went downstairs to get on the train to go to Pompeii. It was a 20 - 25 minute train ride from downtown Naples to Pompeii

You can reach Pompeii by Circumvesuviana, a local commuter train connecting Naples to Sorrento, and stopping at all the important achaeological sites in-between. Tickets are priced depending on the length of your journey, and are valid for a certain number of minutes, including return trips (if they are within the time limit). Buy your ticket directly at the station, and if there is time remaining at the end of your trip you can use it to connect with local city busses. You can see ticket prices at the site below.

Main Stops: Napoli Centrali Train Station (lower level), Pompeii Scavi (archaeological site), Ercolano (archaeological site), Sorrento (via degli Aranci, five minutes by foot to city center).

Many people report having purses or wallets stolen on this train. I personally did not have any problems, nor did my family when they visited. It's always best to keep your hands on your purse at all times, and to keep your valuables where wandering eyes (and hands) can't see them!

The best way to get from Pompei to Naples without driving there, (I've heard the drivers in Naples are not the best!), is to get the train. You can catch the train from Pompei's main station in Piazza XXVIII Marzo which is south of the town's main square. The trip takes about 30 minutes and costs about 3/4 euros return.

To get to Naples, see www.trenitalia.com, and choose "Napoli Centrale" as your destination.

Once you are in Naples, you can take either the "circumvesuviana" train (a private train), or the FS (trenitalia pr national train) to Pompeii.

The circumvesuviana train stops at Pompeii Scavi, which is the front gate to the excavations. If you take the FS train, you will get off at Pompeii on the other side of town from the excavations...not to worry, as the walk through town is only about 15 minutes...but the circumvesuviana is more convenient...

Did this trip in August 2010.
Trains from Rome vary a lot in terms of cost and times,
to check this before you travel.

Took me 2 hours to Napoli (sheer third world hell on earth)
and then a separate train (bound for Sorrento) to Pompeii.

I left Rome about 6.30am and got to Pompeii about 9.30.
This missing the thousands of coach parties that see to get there around mid-day.

You'll need a good 3-4 hours to do Pompeii.

Pompeii has a train station on the Circumvesuviana line, which runs from Sorrento to Naples. The station is only a minute or so's walk from the entrance to Pompeii, and tickets along the line are very reasonably priced. The trains usually have screens on telling you which stop is next, so its very difficult to miss your stop.

great advice...except, take a taxi to the station. It's 10 E each way, and well worth it. Cabbies will hustle you for more euros at the port, but don't pay more than 10 E. The walk is through some seedy areas, and especially after a few hours walking Pompei, you'll want to save your legs.