First think we will need to do is get a repo that is close to you. I see that you are from New York we will want an American Server
Probably one of these
US NY Atlantic Metro Communications http://mirror.atlanticmetro.net/centos/ ftp://mirror.atlanticmetro.net/centos/
US NY BuildDesignCreate.com http://centos.builddesigncreate.com/mirror/
US NY Clarkson University http://mirror.clarkson.edu/centos/ rsync://mirror.clarkson.edu/centos
US NY Columbia University http://mirror.cc.columbia.edu/pub/linux/centos/ ftp://mirror.cc.columbia.edu/pub/linux/centos/ rsync://mirror.cc.columbia.edu/centos/
US NY NYU http://mirror.es.its.nyu.edu/centos/
US NY Rochester Institute of Technology http://mirrors.rit.edu/centos/ rsync://mirrors.rit.edu/centos/
US NY SpinelliCreations http://centos.spinellicreations.com/
US NY Voxel US http://mirrors.lga7.us.voxel.net/centos/
We will then need to install http and createrpo. (You can do this by setting up an http server, creating a directory in there and then rysncing the files but this will be better for a first time)
sudo yum install httpd createrepo
sudo chkconfig httpd on
sudo service httpd start
This will install the http service enable it on runlevels 2-5 and start the httpd service
now under /var/www/html create a directory to hold your files.
sudo mkdir -pv /var/www/html/yumrepo/centos/6.5/os/x86_64/
now lets rsync the files to this directory
sudo rsync rsync://mirrors.rit.edu/centos/6.5/*
now we just need to do the following
sudo createrepo /var/www/html/yumrepo/centos
now just point some of your clients to the http://<server_name>/centos/$releasever/ and further down for each stanza. This was kind of short so if you need more info you may want to do a quick search.
to keep the repo updated just use rsync to download the updates from the mirror that you use. Be warned when I gave these instructions I didn't take security in mind, so there are more ways to secure this.