A judicial internship or externship (the words are synonymous) is the summer equivalent of a traditional post-graduate judicial clerkship, with the exception that most externships do not pay. Do not let this discourage you. These are excellent jobs and can be especially useful to students intending to pursue a career in litigation or to make legal contacts in a community in which they wish to practice.
The American Bar Association provides $1500 to minority and financially disadvantaged students for internships in ten states under their Judicial Intern Opportunity Program. Other states have programs where law students can be paid to work as a judicial intern. North Carolina has such a program for in-state residents.
Many third-year students will apply to clerk for a judge following graduation. While that application process does not begin until the summer before your third year, an externship can not only help you decide if a clerkship would interest you, but may also provide you with a valuable contact within the judiciary.