The best, first advice is to check that your camera is compatible with zoneminder's motion JPEG (MJPEG).
You should read the Documentation. The developers spent and continue to spend a great deal of time writing it... you should spend at least a little time reading it. Specifically, read the part about shared memory.
Recommended IP cameras
Axis brand cameras are a good choice, but expensive.
BSIT are really cheap but also not the greatest quality.
Camera quality varies greatly, both in actual image quality and in operational reliability. Remember that you often "get what you pay for." Cameras from high volume manufacturers may be subject to software/hardware compromises that lower cost at the risk of breaking functionality and/or compatibility with standards.
Avoid cameras that require 1.24(aka: mpeg video) because it make things harder for beginners.
The best beginners hardware and setup is to use an old unused system, anything from late Pentium 3 or Athlon XP generation of cpus will be more than enough for a setup capable of running 2 or 3 cameras depending on configuration.
You will need one of the cheap pci cctv capture cards from Ebay that use the bt878 chip, if you search for pci cctv on ebay then most of the cheap cards that show up will be a card of this type, see the Pico2000 section of the Zoneminder wiki for a few photos of these cards and a little more technical information.
You can alternatively buy them and better boards from the retailers in the shop section of this webpage.
You will need to configure the capture card as described in the Pico2000 wiki
Next source some standard analogue cameras from the retailers listed on this page or any other source you like.
Install Zoneminder using the CentOS guide contained in the wiki or any other distro guide you are happy with, I personally started with the CentOS guide and it has worked well for me.
Configure and then you're running!!!.
This is of course a beginners system and so can be expanded and improved on once you are happy, my aim in this design is to build a Zoneminder system as cheaply and basic as possible, I have made a lots of setups that are still operating on the above basis.