Celoxis is both an online and installable project management platform integreted with Microsoft Outlook, iCal, Google Calendar, and Salesforce.com, among others. Celoxis explains the Celoxis API in a way that suggests they want you to be able to use it easily.
Business Profiles, online database of business registration information, provides access to its massive database via the Business Profiles API. The database contains business registrations (e.g. corporations, limited liability companies, partnerships, etc.) and additional data on shareholders, directors, public filings, and more.