Harvest for Salesforce
Native Salesforce.com integration with the Harvest API. Features Harvest Clients, Contacts, Projects, Tasks integration with Salesforce Accounts, Contact, Opportunities, Projects, and Users.
Installation
To install the unmanaged package: Harvest for Salesforce (Open Source)
To use the source code with a Salesforce org: [How To Use Github and the Force.com IDE] (http://blogs.developerforce.com/labs/2011/04/how-to-use-git-github-force-com-ide-open-source-labs-apps.html)