You'll need an auger to clear the clog in the pipes:
Loosen the clamp at the metal end and begin inserting the snake (metal coily wire) into the pipe until you hit the blockage (or get stuck in a corner).
Tighten the clamp and turn the plastic handle to spin the snake. That will help penetrate the blockage (or realign the snake to get it around the corner).
Extract the snake, clean the end off removing the gunk it collects, and repeat until you stop getting more gunk and the water flows through the pipes again.
PVC is a good choice, provided that it is properly installed and maintained. A proper installation includes shielding the PVC from UV light, which is the primary means of premature aging. UV light will eventually turn PVC into a brittle mess.
ABS on the other hand tends to not become brittle with sun exposure, but to deform and is generally softer. As a result, buried ABS pipe seems to be at a higher risk of crimping, impeding water flow.
In either case, you should paint your exposed pipe, which probably wasn't done, and is the primary reason you are looking to repair it. Personally, I'd go with painted PVC, because after it is protected from UV light, it is less flexible (less pipe collapse) has a wider variety of fittings, and generally has a wider range of temperature distributions. I'm also more familiar with PVC, which might cloud my judgement. I'd love to hear from someone intimately familiar with ABS.
Both types of plastic are generally considered for low pressure applications, if you are having consistent freezing problems, neither pipe is meant to withstand routine freezing of water in-pipe.
PVC UVR is UV light resistant PVC. Buy it and paint it if you want a very long lasting PVC solution. Basically, you will have to worry about the (in my experience) natural enemies of PVC pipe before worrying about aging, that is careless yard crews, people vigorously digging, etc.
Best Answer
In my experience, most horror stories of pool maintenance are usually the result of neglect, or not paying attention to the instructions. It's not that hard, but expect to spend an average of 10-15min per day checking on your pool, adding chlorine, clearing out leaves in the skimmer, etc. Also, once a week, expect to spend some extra time brushing/vacuuming the pool and cleaning the filter.
As a first time pool owner, the simplest thing you can do is pick up a free pamphlet on pool care. Follow the instructions in the pamphlet, and make sure you stay on top of it. My Wal-Mart usually has pamphlets by HTH Pools next to their chemicals.
Start by getting a test strip kit. You dip the strip in the water and compare the colored pads against a chart. Pretty easy (unless you get into a fight with your wife about the shade of orange of the pH pad).
Make sure you pick a good test kit, which measures several properties of the water (should measure pH, stabilizer/CYA, alkalinity, hardness, chlorine). Cheaper ones will only measure a few properties.
Measure your pool every day or so. If the levels are off, adjust them by adding the appropriate chemicals. Just follow the instructions on the container. Most any chemical you need can be found at your local pool store, or Wal-Mart. Beyond that, I'm not going to repeat what you would find in the pamphlet. (Did you get one yet?)
One bit of advice that wasn't in a pamphlet: If you buy "stabilized" chlorine products, they will raise the level of stabilizer/CYA in the pool. If your CYA levels are already high enough, the stabilized product can push your levels over the top. If you aren't sure if the product is stabilized, look for the words Dichlor or Trichlor in the ingredients. Un-stabilized chlorine is usually Calcium Hypochlorite or Sodium Hypochlorite.
Beyond the chemicals, there will be some "mechanical" maintenance/care:
Dirt, pollen, and algae will naturally collect in all the crevices of your pool, so use a pool brush to break it up. Regular churning of the water (from brushing or swimming) will give the filter an opportunity to suck up the debris before it settles.
You will need a vacuum (manual or automatic) to suck up non-floating debris. 48 hours before vacuuming, shock the pool to make sure any algae is dead. 24 hours before vacuuming, add some clarifier to make the algae and dirt settle on the bottom (where the vac will get it).
Make sure your filter is clean. There should be a pressure gauge on the filter that will indicate when too much crud has built up in it (pressure levels will go up). At that point, you need to clean it. Some filters are cleaned by backwashing. Others have a cartridge that needs to be changed. The filter should come with some instructions on how to care for it.
Check the strainer baskets in your skimmer and pool pump. Larger debris like leaves and large bugs will collect there. Periodically shut off your pump and scoop the crap out.
A plugged filter or strainer basket will strain your pump, and maybe cause a burst hose (very bad). So, keep the water path clear.
If you have cold winters, make sure you follow the instructions on winterizing the equipment. I disconnect my pump and bring it indoors every year.