Current zsh in Fedora/Rawhide is 4.2.x which does not support Unicode at all.

As FC6 and RHEL5 are nearing their releases please consider upgrading zsh to
4.3.x which will be released as stable zsh-4.4 stable in mid-October(1),
allowing RHEL5 to use the stable 4.4.

Upgrade would provide Unicode support for years to come that RHEL5 is supported
and I think this would outweight any concerns that might arise from the fact
that zsh-4.4 is not yet released. Also, in Fedora Core using a beta/RC has never
been a problem, so the upgrade should be ok in all aspects, allowing users fully
enjoy the wonders of UTF-8.

Thanks.

1) http://www.zsh.org/mla/users/2006/msg00872.html