| Open Source Alternative Helps to find the open source software alternatives for commercial products. | |
| Open Source Scripts Provides open source software and script directory that serves as resource for open source applications. | |
| OpenCyc Open source version of the Cyc technology serves as common sense reasoning engine. | |
| OpenScience Project Service includes to writing and releasing free and open scientific software. | |
| OpenSource.org Features information and resources for open source software development. | |