It seems the MidCOM PEAR channel is incompatible with the PEAR 1.4.7 release. When you try to discover the PEAR channel you get:
# pear channel-discover pear.midcom-project.org
Discovery of channel "pear.midcom-project.org" failed
Until this issue is resolved you can use the MidCOM channel by downgrading PEAR:
# pear upgrade -f PEAR-1.4.6
If somebody wants to help debug this, the channel server was installed using these instructions. The channel.xml is also available.
Updated 15:00: Seems we ran into a bug in PEAR 1.4.7. Bug #6960 contains a patch. Thanks to Greg Beaver for the fix!
Updated 2006-03-04: PEAR 1.4.8 is coming soon containing a probable fix to this problem.