If you've ever worked with classmates on a program, you probably already have a sense of what it means to be a good programmer. As you become more advanced and experienced, the differences between good programmers and bad programmers will change some... but not a lot.

You also may be interested in Joel Spolsky's views on what employers should be looking for in a programmer. It's at http://www.joelonsoftware.com/articles/GuerrillaInterviewing...