|Subject: Re: Help with Greek Islands|
Here are a few suggestions in answer to your questions - I haven't been to the islands since the 1990's but the websites I've recommended do work!
You asked: My plan is to stay to 3 or 4 different islands but I don't know if it's relatively easy to find a boat or a ship to transfer from one island to another. Of course it depends which islands you want to go to, and as others have told you, it depends on the route the ferries take with Piraeus (30 mins on the metro from Athens) and Rafina (about an hour east of Athens by bus) being the hubs from which they operate. If you are outside the peak season the ferries are much less crowded although in the really low season they are also a lot less frequent. Everyone has horror stories about delays, ferries that don't arrive etc. For what it's worth, after 2 visits to the islands which involved quite a lot of ferry travel I've only had one serious delay - about 3 hours. You've already had one useful website recommended - here's another: http://www.greekislands.gr/
You asked: If I rent a car in Athens, can I put it on these ships too? Or is better to rent at each island a new car without being forced to ship them with me?
Yes, the ferries take anything and everything as far as I could see, but as others have suggested, it would be much cheaper to hire cars on the islands. Depending where you stay you probably won't need a car every day and on some islands you may prefer the cheaper option of a motor bike (maybe things have changed nowadays but it used to be a very popular option).
You didn't ask which islands were good to visit but as everyone else has made suggestions I'd like to add my favourites - Tinos and Crete.
Tinos because it is mostly popular with Greeks and so not so full of non-Greek tourists. The cathedral is a very important place of pilgrimage though, so some weekends accommodation in the town (called Tinos too) is very fully booked. It's easy to reach by ferry (2 - 4 hrs depending how you travel) from Piraeus or Rafina and you can go on to Mykonos and there are connections to several other islands, including Santorini, without going back to the mainland. Incidentally from Mykonos you can get a short trip to Delos, not to be missed, and I expect there is still a direct exursion from Tinos to Delos in the high season. You've already had a recommendation to go to Crete.
I'd just add that my personal preference would be to take a ferry to Hania rather than the much bigger and less pleasant island capital of Heraklion - it's got a lovely old town with a Venetian waterfront. If you like the great outdoors don't miss the walk through the Gorge of Samaria, which starts with a bus from Harnia - see http://www.interkriti.org/visits/samaria/samaria.htm for details - it's one of the most interesting and varied one day walks I've ever done - and it's all downhill!
Enjoy your trip. Michael Sydney, Australia