I've started an Amazon micro instance and assigned it an elastic (static) IP address. I can't seem to figure out how to set up the nameservers that the domain registrar requires.
if anyone can walk me through this, it'd mean the world.
Find out where your DNS is hosted. It's probably hosted with whoever you registered the domain name with-- godaddy, joker, networksolutions, register.com, whoever.
Log in there and look for an option to "manage DNS"
Next, create an A record for .yourdomain.com pointing to the static IP address for amazon. Create a CNAME record that points www.yourdomain.com to yourdomain.com
You'll want to create MX records for whoever is hosting your mail-- I recommend gmail, and they'll give you a list of 5 or so addresses to be MX records for you. Alternatively, your registrar may do mail forwarding. Just make sure you set "email@example.com" to point somewhere, in case there's an issue.
It's definitely worth reading this as well: http://realprogrammers.com/how_it_works/DNS/overview.html
Take a look at a service like http://www.everydns.com/ . You probably don't have decent DNS servers that came with the domain. You also probably don't want to be running your own DNS servers (the DNS RFC says you should have two separate servers on two different subnets)