I just tried to update my centos 5 install via yum and got the following error messages:

filelists.sqlite.bz2                                                                                                                                                                 | 1.5 MB     00:01     
http://centos.eecs.wsu.edu/5.4/updates/i386/repodata/filelists.sqlite.bz2: [Errno -1] Metadata file does not match checksum
Trying other mirror.
filelists.sqlite.bz2                                                                                                                                                                 | 1.1 MB     00:00     
http://mirror.facebook.net/centos/5.4/updates/i386/repodata/filelists.sqlite.bz2: [Errno -1] Metadata file does not match checksum
Trying other mirror.
....

I searched on line for “yum update Metadata file does not match checksum” and found a helpful blog post. Following the post suggestion, I ran yum clean all, which seems to have fixed the problem.