If you have a problem with PEAR which comes with PHP 5.2.10 and receiving messages like “pear.php.net is using a unsupported protocal” most probably you have broken PEAR channel data files located at PREFIX/lib/php/.channels/. You need to replace them with files from working installation of PEAR.
Here is an archived .channels/ folder with working data files.
Update: Official solution is simpler – just remove .channels directory and run
cd `pear config-get php_dir` rm -r .channels pear update-channels