Does 'yum search' work?

[Shawn Milo <shawnmilo runbox com>]

When I try 'yum search packagename', I get an error which says
that "Error: command not implemented yet".

Am I doing something wrong, or is there actually no search option?
If there is no search option, is there an online resource which
will let me search for package names so that I know what package name to 
type in for "yum install packagename"

Thanks,
Shawn