For newer versions of Mac OS X

guide.sh

# Install pow
$ curl get.pow.cx | sh

# Install powder
$ gem install powder

# See Pow takes over port 80 in the firewall... even though nginx was using it...
$ sudo ipfw show
00100     0        0 fwd 127.0.0.1,20559 tcp from any to me dst-port 80 in <- THIS ONE!!!
65535 81005 28684067 allow ip from any to any

# Disable it
$ powder down

# See? It's gone!
$ sudo ipfw show
65535 81005 28684067 allow ip from any to any

# fix it with these commands
$ touch ~/.powconfig
$ open -t ~/.powconfig

# paste in these settings
export POW_DOMAINS=dev,test
export POW_DST_PORT=8080
export POW_TIMEOUT=300
export POW_WORKERS=3

#This changes the port to 8080...

# now run these commands to reinstall pow, this is required due to the way Pow only updates the /etc/resolver at time of install.
$ powder uninstall
$ powder install


# Now that is fixed, now just set this wildcard vhost up in nginx and it will work correctly from now on.
    server {
      listen  80;
      server_name *.dev;
      location / {
        proxy_set_header Host $host;
        proxy_set_header X-Real-IP $remote_addr;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
        proxy_redirect off;
        proxy_pass http://localhost:20559; # The real pow port
      }
    }