BOINC (Berkeley Open Infrastructure for Network Computing) is a widely-used software infrastructure for Volunteer Computing. BOINC has two primary components: server software, which is run by research projects, and desktop software which is run by volunteers.
All the projects available through GridRepublic run BOINC server software. GridRepublic was developed in collaboration with the BOINC team, with the primary goal of making it as easy as possible to find and join BOINC-based Volunteer Computing projects, and to manage participation in these projects. And then of course, to spread the word. The hope is that by making it easy to participate, and then by engaging in aggressive community building and outreach, we can significantly grow the volunteer base-- and thus the computing power available for scientific and medical research.
The GridRepublic Desktop software is built from the same code as the BOINC desktop software. It is slightly customized, (1) to simplify installation and integration with GridRepublic's management features, and (2) to improve the graphical appearance of the software.
It is possible to use generic BOINC desktop software with GridRepublic: upon creation of an account the system will detect preexisting BOINC accounts and give appropriate instructions to "attach" generic BOINC clients to GridRepublic.