I\'m hosting a wordpress site on ec2 and I\'m trying to update my theme through the admin screen. Its asking me for Hostname and ftp username and password. Is ec2-xxx.comput
Your hostname would be ec2-107-20-192-98.compute-1.amazonaws.com.
Your username will be the username you use to SFTP to the instance normally - ec2user for some instance types, ubuntu for Ubuntu AMIs, etc. EC2 generally doesn't use passwords, preferring SSH keys, so you'll have to set a password for your account by doing passwd on the commandline.