if you are using windows, download installer.exe from http://www.apachefriends.org/en/xampp-windows.html#641
xampp is a good one to use, its free, am using this for more than one year, very good also more functions, mysql and filezilla...
Wamp Server is quite good if you want a customizable local server, I needed to install Typo3 CMS and Wamp was the best I found for easy setup. Here's the link to the file on sourceforge : sourceforge.net/project/downloading.php?groupname=wampserver&filename=wamp5_1.7.2.exe&use_mirror=internap
hrmm. www.php.net and www.apache.org would be my first guess. though if you want the "lazy man's bundle", go with xampp. www.apachefriends.org
Depends on what you want to do. Do you need a server quick-like without too much work? Then WAMP link given above will work for you. Do you want to install Apache and PHP from scratch for yourself for the learning experience? Then, as ansi said www.apache.org is where you will get the Apache Server, and www.php.net is where you download PHP. Doing it this way is a great way to learn, but it can take some time if it's your first time setting it up. @ansi, "lazy man's bundle"... , that's funny.
i like xampp for my usb flash drive. install it on there and i have a portable web server. but locally on my desktop, i prefer an independant installation of each. easier to keep updated.