First download, compile and “install” V8 from Google
svn checkout http://v8.googlecode.com/svn/trunk/ ./v8 cd v8 make builddeps make native library=shared sudo mkdir -p /usr/lib /usr/include sudo cp out/native/lib.target/lib*.so /usr/lib/ sudo cp -R include/* /usr/include sudo cp out/native/lib.target/lib*.so /usr/lib/x86_64-linux-gnu/ echo -e "create /usr/lib/libv8_libplatform.a\naddlib out/native/obj.target/tools/gyp/libv8_libplatform.a\nsave\nend" | sudo ar -M
Then install v8js via pecl
sudo pecl install v8js-0.4.0 # The latest stable version for PHP 5+ at the time of this writing
Now add extension=v8js.so to your php.ini.