38176 Help! Site running very slow!

Hi, I've got a site which runs several PHP scripts/cron job. Basically it's very, very slow. When server is rebooted it always works fast but within 3-4 hours it takes a long time to display the home page - once the homepage is displayed the site runs fast. I need someone to have a look at it and make any changes required to make it run fast. Please only bid if you can work on it today and if you have experience with this kind of projects (cron, spider, php scripts, MySQL).