How to prepare soil for planting and what are the most versatile plants to grow during Spring and Summer? The planting area is small.

Your location would be helpful because not all veggies grow in all areas.

I've started mine indoors and will be putting out in a couple weeks.
I don't have much room either, so I am going to put a lot in pots of various sizes. (you can use anything for a pot as long as it drains) I can also move them if they are getting too much sun or not enough.
I dream of having a space to rototill and plant and harvest every year, but doesn't look like that's going to happen, so I just make the best out of what I have.:)

As J_9 said, your location would be helpful. There are many different "right" answers.

You can find an enormous amount of info here. Helpful Gardener Garden Forum - A friendly place to chat about gardening. (http://www.helpfulgardener.com/phpBB2/)