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Maybe start here: http://www.tonmo.com/forums/forumdisplay.php?18-Cuttlefish-Care
You'll need an established salt water tank / set-up and preferably running for months, and the know how to take care of it.
Not knowing your experience, if totally new to sw aquarium keeping, IMO you have maybe a month or 2 of reading and researching before you should look at any equipment.
Some consider it better etiquette (I have heard the word netiquette as well ), to do some initial internet searching / researching before asking simply, "What do I need". 30 minutes of reading on your own on this site will probably answer your first 20 questions.
Not trying to discourage anyone, but I was given this advice before venturing into sw aquarium keeping. If I asked "What do I need?", the most appropriate answer was, "To educate yourself".
I agree, this is the site to do your research on. You can never research too much, especially since this is a very expensive and time consuming endeavor. Keeping cephs can be very challenging, however I tend to disagree with people when they say only experts should delve into ceph keeping. I went from my first freshwater tank to an octopus and kept her successfully. The most important thing is to plan vigorously, be aware of the time and money you are going to put into your new friend and be diligent about the proper care needed.
cuttles are really hard to find, although you can find eggs at various local fish stores. People here will put eggs up for sale from time to time, check out the "cuttlefish availability" thread under "sources for cephalopods"
all that being said I just wanted to say that ceph keeping, in spite of the work, is enormous fun and you never really stop being amazed at how cool the animals are!