xattr is currently available through PECL » http://pecl.php.net/package/xattr.
If » PEAR is available on your *nix-like system you can use the pear installer to install the xattr extension, by the following command: pear -v install xattr.
You can always download the tar.gz package and install xattr by hand:
Example #1 xattr install by hand
gunzip xattr-xxx.tgz tar -xvf xattr-xxx.tar cd xattr-xxx phpize ./configure && make && make install