Nginx

CentOS:
[nginx]
name=nginx repo
baseurl=http:///packages/centos/$releasever/$basearch/
gpgcheck=0
enabled=1
RHEL:
[nginx]
name=nginx repo
baseurl=http:///packages/rhel/$releasever/$basearch/
gpgcheck=0
enabled=1
Ubuntu 10.04:
deb http:///packages/ubuntu/ lucid nginx
deb-src http:///packages/ubuntu/ lucid nginx
Debian 6:
deb http:///packages/debian/ squeeze nginx
deb-src http:///packages/debian/ squeeze nginx
For Ubuntu 10.04 and newer:
sudo -s
nginx=stable # use nginx=development for latest development version
add-apt-repository ppa:nginx/$nginx
apt-get update 
apt-get install nginx
If you get an error about add-apt-repository not existing, you will want to install python-software-properties. For other Debian/Ubuntu based distributions, you can try the lucid variant of the PPA which is the most likely to work on older package sets.
sudo -s
nginx=stable # use nginx=development for latest development version
echo "deb http://ppa./nginx/$nginx/ubuntu lucid main" > /etc/apt/sources.list.d/nginx-$nginx-lucid.list
apt-key adv --keyserver keyserver.ubuntu.com --recv-keys C300EE8C
apt-get update 
apt-get install nginx
Building Nginx From Source
After extracting the source, run these commands from a terminal:
./configure
make
sudo make install
By default, Nginx will be installed in /usr/local/nginx. You may change this and other options with the compile-time options.
You might also want to peruse the catalog of third-party modules, since these must be built at compile-time.