If you need to have links from your old site redirected to your new site like from the following page http://www.yourdomain.com/horoscope to the new one http://www.yourdomain.com/Divination/Horoscopes.aspx
There are two ways how to achieve this:
1. You can set any redirection in App_Code/Global.asax
2. You can create blank page which will redirect to existing page. This is recommended way.
Since the version 4.0 you can use document aliases (Multiple document aliases).