You can pinch the centers out to make it more bushy.

Right.....just lop the tops off (and dry for seasoning or use to make pesto) and the bottom branches will start to leaf out some more. Basil is a pretty forgiving plant as long as it gets enough water.

Like mentioned above, keep it bushy by pruning.

I just keep pruning them back all summer. I have read and attended conferences about basils, and there are many different ways of pruning. The best that I have found is to prune back any flowers as soon as they start to appear to the first full complete set of leaves below the bloom. Sometimes if the basil has gotten away from me and is in full bloom, I will prune it back by about 1/3 the size of the whole plant.

There are different ways to prune. Some people just snip off the flower, while others take a more radical approach such as mentioned below which is a quote from The Herb Society of America:

Basil should be pruned when it has three to five sets of true leaves to promote branching and maximize growth. For the first pruning, cut the plant back to just above its second set of leaves. Material for freezing and drying or making oils, butters, pesto and vinegar should be cut throughout the summer from young leaves, since older leaves have less oil content and become tougher. Though basil is heat-loving and will grow strongly all summer, as soon as nights go below 50°F it shows signs of deterioration.

Also make sure it gets adequate light, water and occasionally you might want to give it a fish/seaweed emulsion foliar spray.

I just brought some sweet basil from the 99 cent store. Its like a small bush. Whats the best way to take care of it? It south on my balcony and its south facing balcony. When ready to use for cooking i just snip what i will use and dry before use?

Mine has already started going to seed.

My basil (all 46 bushes) are getting pretty big. The ones I planted last year were 4 feet tall and almost as wide at halloween. I used a bush pruner to cut them back. Keep pruning and watering and you too will have trees.

Do you have any idea how much basil is in a 4 x 3 bush? I'm talking lots of pesto.