svn checkout https://setisvn.ssl.berkeley.edu/svn/seti_boinc
The client code is in client/; sample input files are in client/test_workunits.
If you are looking for the SETI@home CUDA source, it is currently located at https://setisvn.ssl.berkeley.edu/svn/branches/seti_cuda. It will eventually be merged with the main source branch.
You can compile SETI@home for new platforms, or (if you know what you're doing) compile it or revise it to run faster on an existing platform. In either case, you'll need to know about BOINC's anonymous platform mechanism.
firstname.lastname@example.org is an email list for people porting and optimizing SETI@home and other BOINC applications. Sign up for it here.
Executable versions of BOINC and SETI@home for various platforms are
©2016 University of California
SETI@home and Astropulse are funded by grants from the National Science Foundation, NASA, and donations from SETI@home volunteers. AstroPulse is funded in part by the NSF through grant AST-0307956.