Beginners Guide

Question
Hello! I am an intermediate freshwater aquarist (i dont know if thats the word), and i want to start on a simple saltwater tank. Here are my questions:
1. What is the biggest difference between freshwater and saltwater?
2. What is the recommended minimum saltwater tank size?
3. What are some great beginners' fish?
4. Other things i need to know like supplies, skimmers, sump, (i dont know what those do)

thank you for your time.  anything you write is appreciated

Answer
Adam,
I generally recommend beginners or people interested in starting in the hobby to pick up a copy of Bob Fenner's The Conscientous Marine Aquarist book.  It's very easy to read and covers everything you're gonna need to know from start up to long term maintenance.  It even has a species guide in the back to help you with picking your fish.  Additional details about the book can be found via our online catalog at www.aquariumcrazyfish.com

But, to answer your questions...
1)  Honestly, the only major difference between fresh and marine aquariums is the addition of salt to the water.  Sure you have to keep a closer eye on the pH and you really can't cram as many fish into the tank as you can in fresh, but with the products we have now-a-days it is pretty hard not to be successful with a marine aquarium.
2)I'm always going to recommend as big as you can afford in your budget and afford to give up space to in your house.  I really wouldn't go any smaller than 29 gallons.  In a tank that small you can only have a like 4 smaller species of fish and because it's such a small volume of water it is easily influenced by the environment around it.
3) I always recommend that you look at a species guide and select what fish you ultimately want to have in the tank.  From there a decent fish store should be able to point you in the direction of species that are compatable with said fish.  Damsels and Clownfish are always a hardy starter... but long term can be territorial and aggressive.
4) Other things to know... hmm... I'd say get the Fenner book to get details on skimmers, etc.  Other than that, be patient with the tank and resist the urge to overstock.  Mother Nature has a nasty way of dealing with those situations.  Common sense goes a long way in this hobby.

Best of luck with your new hobby!

Regards,
Scott Johnson
Aquarium Crazy Fish
www.aquariumcrazyfish.com