Moving from static pages to pages served by server-side scriping will give your web-server a lot more to work.
250000 page views = around 3 page views a second on average. Considering that web-traffic is seldom distributed in an average way, my guess is that you will often have 10 page views per second during peak hours. This could seriously slow down your server's response time - especially if you start using a database-system with your PHP.
Remedies:
1. Look into making your web-pages cacheable by the browsers. That could be done by using PHP's header() function with code like this:
define('HTTP_DATE_FORMAT','%a, %d %b %Y %R GMT');
$later=time()+10800; // 3 hours later
header('Expires: '.gmstrftime(HTTP_DATE_FORMAT,$later));
Remember that the header() function must be used before any other page output.
Move to PHP 4. It has better memory management and is quicker for most operations.
Serve static URLs (like images) through a light-weigt web-server like thttpd or boa. If you configure the light-weight web-server to listen to port 81 instead of the normal HTTP-port (80), then you could refer to images like:
<img src="http://mywebserver:81/logo.gif" width="xxx" height="yyy" alt="[Logo]">
Better hardware (use a fast SCSI-disk if you don't already; put in more RAM; perhaps an extra CPU if your pages start getting complicated).
You could also consider putting a proxy up in front of your web-server. E.g., you could have Apache listening on port 81 and the proxy ("Squid" is probably a good choice) serving requests on the normal port (80) - thereby server-side caching Apache's output. This would make point 1 and 3 above irrelevant.
