PHP DateTime Class和time_zone / stamp off

For my web application I'm using a PHP class to align the dates and times used in various formats like stamps and dates. My application is a webcrawler and also a custom Twitter app. Both require daily reports and this makes accurate time keeping crucial. Even more so as I use the Unix timestamp format for database store across the whole application. This makes calculations much easier for me. The system design is that it creates a timestamp for a single date by setting the Unix time stamp for the date at time 00:00:00 hour. I call this todayStamp00 for instance. For my web application I'm using a PHP class to