Basic apache .htaccess authentication

To restrict access to a specific directory
Create a .htaccess file in the directory that you want to restrict
AuthUserFile /path/to/.mypasswds
AuthGroupFile /dev/null
AuthName "Title for password box"
AuthType Basic
require user username
require user user2 # you can add more users by setting multiple require statements
# Require valid-user  # you can allow any user listed in password files.

To generate an encrypted password
Execute this shell command which will create the file .mypasswds with a hashed password entry
htpasswd -c /path/to/.mypasswds username
New password: password
Re-type new password: password

Enable the configuration
The module mod_auth must be loaded in Apache2 config
LoadModule auth_module modules/mod_auth.so
Edit the Apache2 config files to set the AllowOverride for the directory you want to protect
<Directory "/var/www/html">
Options Indexes FollowSymLinks
AllowOverride AuthConfig
</Directory>

http://www.yolinux.com/TUTORIALS/LinuxTutorialApacheAddingLoginSiteProtection.html
http://engr.oregonstate.edu/computing/web/43
http://httpd.apache.org/docs/2.0/howto/auth.html

Compile PHP 5 From Source

Before configuring, you must have development versions of the given packages installed. For example, for mcrypt support, you must install mcrypt-devel. In the list below, this applies to zlib-devel, libxml2-devel, mysql-devel, bzip2-devel, httpd-devel, and mhash-devel. Some configure options below didn't require a development version.

View configure options
./configure --help
Many configure options allow an optional =/path syntax to allow you to specify a non-default location for the development libraries.

Special configure notes
The --prefix config option allows you to specify a non-default location to install the php distribution (The root of the install, if you will)
The --exec-prefix directory allows you to specify an alternate location to install the compiled PHP binary files. In this example, they are set to the same location in the /opt directory.
Highly recommended to install --with-apxs (Apache 1.x) or --with-apxs2 (Apache 2.x). This creates the Apache module called libphp5.so that is normally installed in the Apache modules directory. This module is what Apache uses to run PHP web sites (and not the command line PHP program from the --prefix directory).

Configure command
./configure \
--prefix=/opt/php5/dist \
--exec-prefix=/opt/php5/dist \
--with-mysql \
--with-pdo-mysql \
--with-zlib \
--with-bz2 \
--enable-zip \
--with-openssl \
--with-mcrypt \
--with-mhash \
--with-curl \
--with-gd \
--with-jpeg-dir \
--with-png-dir \
--with-ttf \
--with-apxs2 \
--enable-ftp \
--enable-exif \
--with-freetype-dir \
--enable-calendar \
--enable-soap \
--enable-mbstring \
--with-libxml-dir=/usr/lib

Brief explanation of given config options
--prefix=/opt/php5/dist # sets where the root of the install will be
--exec-prefix=/opt/php5/dist # sets where the root of the binary install will be
--with-mysql # add mysql support
--with-pdo-mysql # add support for php mysql database abstraction layer
--with-zlib # add support for compressing using zlib
--with-bz2 # adds support for bunzip2
--enable-zip # adds zip compression support
--with-openssl # adds openssl functionality
--with-mcrypt # adds support for mycrypt style functions (encryption)
--with-mhash # adds special hashing functions
--with-curl # adds support for cURL which
--with-gd # adds support for manipulating images with php
--with-jpeg-dir # adds support for manipulating jpegs with php
--with-png-dir # adds support for manipulating png files with php
--with-ttf # adds support for manipulating true type fonts
--with-apxs2 # adds support for apache2 module (important)
--enable-ftp # adds support for php ftp
--enable-exif # adds support for manipulating Image metadata
--with-freetype-dir # adds support for FreeType2
--enable-calendar # don't know
--enable-soap # adds support for SOAP XML stuff
--enable-mbstring # multi-byte string support
--with-libxml-dir=/usr/lib # adds XML support (required)

Compile and install PHP
make | tee output.make
make test | tee output.maketest
make install | tee output.makeinstall

Special notes about the compile
When using --with-apxs or --with-apxs2, the libphp5.so will be compiled in the "libs/" directory of the PHP source code. The make install will try to copy this automatically to your Apache modules directory. (In the case of the above example, make install placed the module in the /etc/httpd/modules directory - this is really a simlink to /usr/lib/httpd/modules/ in this case.)
The command line PHP binary will be located in the bin/ directory of the path specified by the --prefix option.

Install the mod_php shared library into apache
After a compile of php with the --with-apxs or --with-apxs2, and placement in the /etc/httpd/modules directory (as mentioned above), the module needs to be referenced in the httpd.conf
LoadModule php5_module /usr/lib/httpd/modules/libphp5.so

# Also, the following needs to be added to the httpd.conf

# Cause the PHP interpreter to handle files with a .php extension
AddHandler php5-script php
AddType text/html php

# PHP Syntax Coloring
AddType application/x-httpd-php-source phps

# Add index.php to the list of files that will be served as directory
DirectoryIndex index.php

http://dan.drydog.com/apache2php.html
http://us.php.net/manual/en/configure.php#configure.options.servers