WebIssues is a multi-platform system for issue tracking and team collaboration. It can be used to store, share, and track issues with various attributes, description, comments, and file attachments. It is easy to install and use but has many capabilities and is highly customizable. Desktop and Web clients are provided.
Teamwork is a Web-based groupware for project management. It supplies groupware, issue tracking, cost control, and document and project management features with fine-grained security in a friendly interface. Agile methodologies such SCRUM are supported. Teamwork is easy to integrate with your IT infrastructure. Supports multiple databases (via hibernate), browsers, and languages.
Interleave is a Web-enabled business process automation application. It enables you to model your business process like purchasing, project management, and contract management and make it available online. It's meant to replace processes which currently rely on paper, email, or spreadsheets and it has a very good workflow engine. You can create invoices, export to RTF and PDF based on templates, export to MS Excel, interpret incoming email, and publish your data to the Web.
The Apache Open For Business Project is an enterprise automation software project that includes ERP, CRM, E-Business/E-Commerce, SCM, MRP, and CMMS/EAM functions. It is a foundation and starting point for enterprise solutions and can certainly be used out of the box, but is also great for creating specialized applications.
ITracker is a Java J2EE issue/bug tracking system designed to support multiple projects with independent user bases. It supports features such as full i18n support, multiple versions and project components, detailed histories, issue searching, file attachments, dynamic reports with charts, configurable field values, customizable project level fields, pluggable authentication, a built-in scheduler, and email notifications.