NOTE: This is only available for Asterisk-cnet 1.4 at the present time.
If you're running Enterprise Linux (e.g. Red Hat, OEL, CentOS, or Scientific Linux), an autoinstall script is available to automate the installation of asterisk-cnet and dahdi-cnet. This is for new installations only; I recommend that it be used on a fresh install (be sure to do an initial yum update first to pull down the latest kernel!)
It will install the Repoforge repository for you, download and install prerequisite packages, and download and install my modified Asterisk and DAHDI packages. Do not use this to upgrade an existing installation.
It is preconfigured for use with EL5 i386. You can edit it for CentOS 6 and/or x86_64 if you need to do so. Just download it, read it over if you're paranoid, and invoke it as root with sh cnet-o-matic.sh to run the install process.