After downloading the file (say, into file X), type
sh X
This will create a directory BOINC/ with the following files:
boinc
The BOINC core client
boincmgr
The BOINC manager
run_client
A script that cd's into the BOINC directory and runs the core client.
You may want to run the executable each time your machine boots or you log on. Information on this is here. "; page_tail(); ?>