On CentOS/RHEL (+cPanel) installations, if you get a "checking whether the C compiler works... configure: error: cannot run C compiled programs", you may need to remount the /tmp and /var/tmp with exec permissions first:
$ mount -o remount,exec,suid /tmp
$ mount -o remount,exec,suid /var/tmp
Then:
$ pecl install {package}
And, don't forget to remount them as noexec after.
If you are using a Debian sarge system (currently the stable release) with php4-pear installed, you will still not have a pecl command.
The fix to this is to upgrade pear.
Unfortunately, pear upgrade PEAR will also error out stating that you need pear-1.3.3 minimum.
The fix to this is to specify the version of pear that you want to install. In case it wasn't obvious, that means you want to
pear upgrade PEAR-1.3.3
pear upgrade-all
