ZAP! is a module which makes it fairly straightforward to build WWW-based user interfaces for groups of Z39.50-based information resources. It hides much of the complexity of the underlying protocol and requires mostly an understanding of HTML and some understanding of the Z39.50 database model.
OpenIsis provides a library and tools to access CDS/ISIS databases, which are mostly used for bibliographic data (ISO2709, Z39.50) but also well suited for other catalogues due to the very flexible indexing mechanism. Based on a C library, there are also bindings for Perl and Java (Tcl to come).
YourPay is a PHP class that can be used to submit WorldPay transactions through a WorldPay account without the very impersonal payment pages provided by the said company. This class will submit the user's credit card details in real-time and return either "Authorise" or "Decline" according to the response.
Emilda is an Integrated Library System that features an OPAC, circulation and administration functions, Z39.50 capabilities, and 100% MARC compatibility. MARC compatibility is achieved using the Zebra server from Indexdata in conjunction with MySQL. Emilda is mainly written in PHP, but Perl scripts exist for MARC manipulation and shell interaction.
The Virtual Data Center (VDC) is a digital library system "in a box" for numeric data. It provides a complete system for the management, dissemination, exchange, and citation of virtual collections of quantitative data. It provides everything necessary to maintain and disseminate an individual collection of research studies: including facilities for the storage, archiving, cataloging, translation, and dissemination of each collection. On-line analysis is provided, powered by the R Statistical environment.