Software Development Lohninger
This site offers software and programming components for Delphi and C++Builder covering mathematics, statistics, scientific graphing, and chemistry.

The Chemistry Development Kit
Java based computational chemistry package which supports chemical structure drawing and the graphical layout of 2D chemical structures.

Open Babel
Open-source C++ library for molecule file conversion and pattern matching.

Molecular Modelling Toolkit (MMTK)
A library for molecular modelling applications.

CACTVS System
A distributed client/server system for the computation, management, analysis and visualization of chemical information of any type. Tool collection for several Unix flavors; some of the tools are distributed freely in precompiled form.

PerlMol
Free Perl modules for molecular chemistry. Tutorial, reference manual, downloads and mailing list.

JOELib
Java computational chemistry library which supports file conversion, SMARTS substructure search, QSAR descriptor calculation and process/filter methods for molecular data sets.

JChem
A Java based development tool for building portable chemical information systems.

PDB2VRML
Free Perl module for converting PDB files to VRML for 3D visualization.

pdb2vrml
Free C++ library for converting Protein Data Bank (PDB) files to Virtual Reality Modeling Language (VRML) worlds.

Frowns
Free chemoinformatics toolkit geared toward rapid development of chemistry related algorithms. Written in Python with a small portion written in C++.

The Octet Project
Open-source, object oriented cheminformatics framework written in Java.