skeeter ca,
My suggestion would be to pressure wash loose material off. If you have algae then give it a chlorine wash. You can sand the rough spots with a power sander or by hand with 60 grit wet and dry. I would prefer you just gets things reasonable smooth and use the pool rather than painting it.
Use an algicide when you get the pool running to help wet the water and slow the growth of algae in the rough spots. Good luck.

There is a problem leaving a pool empty. Unless you install what I believe is called a hydraulic plug, the pool will start to come out of the ground.

Painting it will cost at least 1/2 of what a white plaster job will cost. Paint typically last 1-3 years.

White plaster lasts about 10 years. Plus you'll get to use the pool.

Painting, waiting a couple years and then plastering will also add the paint removal cost, eating most of the cost delta you thought you were saving.

Leaving it empty would leave you susceptible to any of the following: a deteriorating shell, a smelly mess of stagnant water loaded with mosquitoes and bio-badies like staph, west nile, etc... and a visit from the township/county health department or code enforcement officers, courtesy of the neighbor's complaints.

Removal will cost a lot more than a plaster job.

Just being straight with you.

Scott

I think Scott makes some valid points, but if you're still going the painting route (I know how the money goes...), you can take a look at the paints mentioned below. I've talked with a few people who have been happy just going with paint to deal with some of their "blemishes" while others have wished they'd gone the plaster route from the start as Scott mentioned.

Here's a quick article that will probably give you a decent idea of the labor you're in for also. http://www.ehow.com/how_17436_paint-swimming-pool.html

Here is a link that might be useful: pool paints

This is a very common problem. Concrete pools are actually not meant to be painted and many pool builders will scoff at the notion. The reality is that pool plaster is expensive, and also usually tied to tile, coping and plumbing renovations which can add up to many tens of thousands very quickly. If you can't afford it...you can't afford it...what can you do?

I wrote a tutorial specifically for people in this situation. As pointed out by another comment if you paint your pool now you need to worry about sandblasting the surface when you do get around to plastering (which is big $$) and also the painting cost itself can be half as much as a plaster job. Unless you do it yourself, and do it using a paint that is water based so that you will not need to sand blast in the future. If you want to take this on yourself, I do caution that this is a bandaid solution

and a new plaster is much better...if you can swing it financially. If that is simply not an option for you then paint it yourself using this specific process. All in you can do it in a weekend for under $1000 and it will buy you 2-4 more years while you save for a plaster. Since the paint I recommend is non-building and water based you can remove it almost completely with a 3000+ PSI pressure washer when you are ready to plaster - no sandblast needed. I hope this helps! How To Paint A Pool For Cheap