i have been thinking about this simulated cron thing as well. There are a number of small things i wanted done on a daily/hourly basis and it would be nice if i could put them all in a script called daily.php that got excuted, well daily
But not sure the best way to do it. What you need is somewhere a date value and then use one php page to get the data value and compare it to CURDATE() and if 1 day apart than include daily.php
Now, it would be easy just to have another query to check the date but that is quite inefficient. If it was a setting then every page would use it. I thought one way would be to add the extra query to register.php and perform the check on the date there. Register.php is a reasonable choice because i know it gets accessed every day but not that often and it also does not have many queries on it already. For those with less traffic i would think search.php would be good (low queries) or maybe usercp.php but that is a higher amount.