For starting to run SETI@home for BOINC, go
here
and "activate account" if have an account in "classic" before 14. May 2004 and has access to the email-address, otherwise create a new account.
By following the steps on the web-pages, you'll get to the "preferences"-page. For most the default should work, but if multi/HT-cpu, make sure to set "On multiprocessors, use at most N processors" to how many cpu's you max wants to use, each HT counts as 2. Also set "Connect to network about every N days".
After accepting the preferences, you'll be transferred to the download-page for BOINC, current version is v4.13
After installing BOINC v4.13, you need to "attach", as url use
http://setiathome.berkeley.edu/ and as account-key use the long id in the email you got then activating/creating new account.
Note, if you needs to set some proxy-settings, you must do this before "attaching".
If everything works, it should now start to download work & the seti-application, current version 4.08 for windows, v4.02 if other OS, and start crunching.
If you couldn't activate an old "classic" account, or wasn't part of Anandtech and wants to join this team, go
here and click "Join team"
Note, you'll not show up in the team before you've got any credit.
BTW, Berkeley have still not "officially" announced when "classic" is ending, so for the moment you can still run "classic" if you wants to, but you must probably upgrade to BOINC 1st quarter 2005 if you wants to continue running SETI@home.