Instructions are all on the boinc site.
The Project Builder project file has never worker as far as I know, so you use the command line.
Download a tarball, or check out current source from the cvs server, cd into the directory in terminal, set and compile flags you want and type
./configure
when done cd into client and type
make

Seti worker is about the same only the seti directory needs to be in the boinc source directory since it links with liboinc and uses some of the client source.