Situation:
WAMP installation on Windows XP SP 3 on C:\wamp\
Dynamic DNS account at www.dyndns.com ( I will use domain.dyndns.org ).
Solution:
1. Open c:\wamp\bin\apache\apache2.2.8\conf\httpd.conf
2. Find line: ServerName localhost
3. Replace with line: ServerName domain.dyndns.org (Or you can comment it, it will work, but you will get a warning in apache log)
3. Scroll down to the end of the file and add:
NameVirtualHost *:80
#default root
<VirtualHost *:80>
DocumentRoot „C:/wamp/www”
ServerName *.domain.dyndns.org
ServerAlias localhost
</VirtualHost>
#subdomain
<VirtualHost *:80>
DocumentRoot „C:/wamp/www/subdomain”
ServerName todo.domain.dyndns.org
ServerName todo.myweb
</VirtualHost>