You might be looking for the php-pear and related packages, from its description:

This package contains the base PEAR classes for PHP, as well as the PEAR installer. Many PEAR classes are already packaged for Debian, and can be easily identified by names beginning with "php-", such as php-db and php-auth. Note: to build and install precompiled PECL extensions, you will need one of the php development packages installed.

You might find these packages helpful:

# apt-cache search php- |grep -i pear
php-auth - PHP PEAR modules for creating an authentication system
php-date - PHP PEAR module for date and time manipulation
php-db - PHP PEAR Database Abstraction Layer
php-file - PHP Pear modules for common file and directory routines
php-html-template-it - PEAR HTML Template IT
php-http - PHP PEAR module for HTTP related stuff
php-image-canvas - Image_Canvas module for PEAR
php-image-graph - Image_Graph module for PEAR
php-log - Log module for PEAR
php-mail - PHP PEAR module for sending email
php-mail-mime - PHP PEAR module for creating and decoding MIME messages
php-net-imap - PHP PEAR module implementing IMAP protocol
php-net-lmtp - PHP PEAR module implementing LMTP protocol
php-net-sieve - net_sieve module for PEAR
php-net-smtp - PHP PEAR module implementing SMTP protocol
php-net-socket - PHP PEAR Network Socket Interface module
php-sqlite3 - PHP SQLite3 PEAR module
php-xml-parser - PHP PEAR module for parsing XML
php-xml-util - a XML utility for php-pear
php-pear - PEAR - PHP Extension and Application Repository

Installing the required packages should be as easy as:

apt-get update
apt-get install php-pear ...

Note: you will probably also want the php5-dev package if you are doing development.

Hope the above helps, good luck!