If you want to extract the contents of an RPM to the current directory without installing it, run the following:

rpm2cpio foo.rpm | cpio -idv

NOTE: wildcards are acceptable when specifying a packages name

searching for a rpm

$ yum search nagios*

listing rpms

$ yum list all
$ yum list available
$ yum list installed
$ yum list updates
$ yum list recent

download/install updated rpm packages

$ yum update

exclude a package

$ yum update --exclude=nagios-plugins*

exclude multiple packages

$ yum update --exclude=nagios-plugins* --exclude=faad2* --exclude=vlc*