To run PHP in your laptop, you have to work on web server(Apache or PWS)+PHP, I think you need database as well.
To get web server, if you prefer to use apache, you should head to www.apache.org to find the correct version for your operation system. You can find the instruction when you extract the software.
To get PHP, you can get it from www.php.net. you can get the readme file from this site. It's a quite power and useful site.
Most of PHP will be based on database, I used Mysql and oracle database. It depends on your application.
All above are brief ideas on making PHP working in your laptop. You have to struggle with these parts, then you will
feel it is not so difficult. Everything is running like a charming.