Connecting to EC2 with Transmit
This example is for Amazon Linux EC2 so your milage will vary. Click the [+] to add a site to transmit:
You need to select sFTP as your protocal, enter either your instance name given to you by AWS or the domain you use to access it. The user will be ec2-user with no password. You should have saved your PEM key file to your local system to you can SSH and manage your instance. I put it in ~/Documents/ec2-keys/[yourkey].pem. Then go to the command line and change directory to the ~/Documents/ec2-keys/ folder in this case and run :
chmod 700 [yourkey].pem
Also a special note you have to do the ssh-add command again if you reboot or logoff.