HD, go to
www.nano-reef.com and read until your eyes are sore. Then check out
www.reefcentral.com - they have a nano forum there, and I haven't seen any better source of reef info out there; any question you have, the answer is probably there somewhere.
I'm still a noob with SW, my reef is less than three months old, but I'll try covering the basics of what you may need. Do loads of research first, it will save headaches. Even with lots of research, I still did dumb things, but at least not too many and nothing too serious
You said you'll have 40W of PC lighting? I think that should be enough to keep some zoas, mushrooms, maybe a few other soft corals but if you can get an 80W or even 96W PC fixture you'll have a lot more options. Check out eBay, there are some good deals out there.
You'll want to have ~10-15lbs of live rock (some is denser than others, so takes up less space, but most people recommend at least 1lb per gallon). The rock is your biological filter, so I'd recommend not skimping here.
Some people skim nanos, others don't - it's up to you if you want to get a skimmer. Personally, I wouldn't want to keep my 14g without one; any gunk that gets pulled out means less NO3/PO4 for my fish/corals to have to deal with, helps me sleep easier. My Prizm isn't great and requires too much tinkering for my tastes, so I've ordered an AquaC Remora - people seem to really like these for nanos but they are a little on the pricey side. Again, eBay is your friend
There's a lot of debate about bare bottom (BB) vs. sand substrates, I chose to use sand and think it's fine as long as it's stirred frequently to avoid trapping all sorts of detritus that may leach PO4/NO3/other stuff later. Apparantly deep sand beds (DSB) don't really work in small tanks so if you go with sand somewhere between 1-2" is probably enough.
You'll want circulation; you can use powerheads, HOB filters (or both) or even mod an AquaClear 70 or 110 into a mini-refugium if you like - I did, and I'm glad; It's a place to keep LR rubble and macroalgae (which reduces nutrients), adds water volume to the system, and provides good circulation in my tank. There are detailed posts on how to mod these filters on n-r.com. I initially used a smaller impeller in my AC70, but have gradually worked my way back up to the original - the corals/fish seem fine with it and it helps keep detritus in the water column for the skimmer to grab. An added bonus to using a HOB is that it provides loads of surface agitation.
When it comes to fish, just remember you can't keep nearly as many in a 10g SW tank as you could in a 10g FW tank! I feel my nano is full with my Lubbock's fairy wrasse and clown goby, because the pistol & cleaner shrimp, 8 snails and corals all add bio load.
My last piece of advice is to consider covering the tank. I thought about going without a glass top, but read too many stories of fish 'carpet surfing' to be comfortable with the idea.
HTH to get you started