how do i start up a saltwater tank?

Im new to this as well but I would recommend a fishless cycle (using a shrimp from the local meat shop will do).

I think the main things you need are sand,salt mis, water flow (see a below), heater, test kit (nitrate, nitrite, ammonia, ph), and a hydrometer to check the salinity level.

a)I have a HOB filter and PH on my 10g and some rock for bacteria and stuff to get on. I think those are the absolute neccesary things you have to have to start. Depending on the size of the tank I think you might have to look into a protien skimmer.

like I said Im starting my new tank right now, havent even put fish in it yet...still cycling. So take my info for what it is worth although I think im right and if not im close. GL with it

Good advice, civicman86.
Tweekerz, I agree-don't put your fish through a cycle-it's much harder on a sw fish than a fw fish.
There is a great sticky at the top of the newbie forum-starting a sw tank-if you read it, it will probably save you a ton of typing! :
Good luck, and welcome to the salty side (or AC, whichever came first!).

i suggest cycling with live rock. ive read some bad things about cycling with cocktail shrimp. and the cylces goes alot quicker, because there is already bacteria on the rock