These should be installable via yum and the base RHEL repositories. Have you tried querying if they are already installed but not in your path? Also, have you successfully installed anything via yum?
To check what package you need to install:
[user@server]# yum whatprovides autoconf automake
Loaded plugins: rhnplugin, security
autoconf-2.59-12.noarch : A GNU tool for automatically configuring source code.
Repo : rhel-x86_64-server-5
Matched from:
automake-1.9.6-2.1.noarch : A GNU tool for automatically creating Makefiles.
Repo : rhel-x86_64-server-5
Matched from: