Congrats! I made the leap to saltwater in January and have been very successful, but also very cautious. I did have sleepless nights when I first set it up, worrying that I may have done something wrong. I'll share my experience and hope it helps you-
I bought an already fully set up 29 gallon biocube, but the seller kept the fish. I took home the established live rock, along with as much water as I could transport. I then went to a my local trusted LFS that specializes in saltwater only, and got reef water from a display tank to fill my tank. I bought a saltwater master test kit, and tracked my ammonia/nitrate/nitrite until the small cycle passed and I added hermits and snails for a cleanup crew. They did well so I started adding corals and fish slowly.
You don't have a lot of options for fish that size, but if you look around for nano fish, you'll find some ADORABLE gobies and blennies exist that max out at 1-2". Mushrooms and zoanthids are excellent corals to start out with, but you will definitely want new bulbs if you don't know if the ones you have are newer. Nanotuners is a pretty good place to get those. I really like dwarf feather dusters too. I continue to buy water weekly from my LFS to do water changes, since I know he's reliable, plus it's cheap, only 1.00/ gal plus it gives me an excuse to go to the fish store weekly!

I did buy an RO/DI unit and I'll learn how to mix my own water when I'm feeling brave.... one step at a time.
If you have any way to do a modification to the type of nano you have to include a small refugium to pack in chaeto, I highly recommend it. I have done that with mine, plus I have a biocube skimmer - not the best, but it works pretty well actually, and much better than no skimmer. I have a chiller on my tank, watch yours closely and make sure it doesn't get too warm. You can prop open the lid and use a fan if heat becomes an issue on really warm days if air conditioning isn't available, but watch out because some fish jump. For filter media, I use Purigen, Chemi Pure Elite, and PhosGuard since that was what was recommended to me by other experienced reefkeepers. My corals are multiplying like crazy, and my fish are doing great. I've even recently added a second nano tank!
Here are vids of my tanks if you'd like to see them:
http://www.youtube.com/watch?v=ksnzH-5Ah-E
http://www.youtube.com/watch?v=dNf3_wyzu30&NR=1
Hope this helps you and good luck!
Shayna