I'm moving my internal server to new hardware and wanting to load CentOS 5.2 ... without downloading a half dozen CDs or a 4+GB DVD image... half of which I probably won't need, or which will be replaced by updates anyway.
Fortunately, the latest releases have a Net install image, which is only about 8MB. Look for this file on the mirrors:
for the 64-bit version, or as appropriate for your architecture.
Booting that CD asks about your keyboard and such, and then asks for an Installation Method. Pick HTTP, and you'll be asked for the website and directory. Strangely, there's no automatic list of mirrors, so you have to do some scouting. I suggest using the mirror from singlehop -- enter this:
Web site name: yum.singlehop.com CentOS directory: CentOS/5.2/os/x86_64
The first file downloaded is
images/stage2.img which is about 90MB,
and then off you go.
If you're setting up a large number of servers, you probably want to either download the ISOs or install a local mirror.