Today's high school students have more options than ever to earn college credit prior to graduation and to take higher-level courses that can better prepare them for college. One popular option is the Advanced Placement (AP) program, which students can take starting in their junior year.

About 60 percent of U.S. high schools and 15,000 high schools worldwide offer Advanced Placement classes. There are more than 38 different AP courses in 22 subject areas -- everything from chemistry and calculus to Japanese language and culture. The program is run by a non-profit membership organization called the College Board.

AP classes are designed to prepare high school students for the rigors of college-level work. To see if your high school offers approved AP courses, check the College Board's AP Course Ledger.

After students complete an AP class, for which they earn high school credit, they can take the AP exam. The exams take place every year in May.

It's also possible to take an AP test without taking the class. If students are home-schooled or if their school doesn't offer a particular AP class, they can still arrange to take an exam. They still earn credit if they get a good score on the exam.

Depending on how students score and what college they plan to attend, they can earn academic credit or "test out" of a college class. It can mean fewer assignments to juggle come college time and possibly even some financial savings.

AP classes are free, but it costs $94 to take an exam. For low-income students, the fee is usually reduced or entirely paid for through state and federal funds or assistance from the College Board, according to the Board's website.

Student exams receive a score ranging from 5 to 1, with 5 being the equivalent of A-level college work. Many colleges accept scores from 3 and up, while more selective schools only consider 4s and 5s as worthy of credit or placement. The scores are reported to the college of the student's choice, unless the student chooses to have them withheld.

Carleton College, a private liberal arts college in Northfield, Minnesota, is one of the more selective schools. Admissions dean Paul Thiboutot says that each college department determines what score is acceptable for credit, but it's generally either 4s or 5s.

Colleges like Carleton are interested in prospective students who are taking the most academically challenging classes available and are doing well in them, Thiboutot says. These could be AP classes or another type of advanced class.

However, if students aren't prepared to do the work required to do well in an advanced class, they should think twice about enrolling in one. They also should keep in mind that colleges are interested in more than just test scores. If taking a number of advanced classes prevents students from participating in other activities they enjoy, or from taking a class that really interests them, they might want to reevaluate their priorities.

"We certainly encourage students to take AP courses and other advanced courses. We also encourage students not to lose sight of having a little fun in high school," Thiboutot says.

Alex Bulitt took four AP classes between his sophomore and senior years at Roxbury Latin School, a private school in Boston for boys in grades 7-12.

Now a senior at Stanford University, Bulitt says all students at his former school were required to take the AP class in U.S. history. He also took AP classes and the corresponding exams in statistics, calculus BC and politics. He took two additional AP exams in physics and chemistry, which earned him college credit or placement.

"My school did not offer any AP-level classes in the sciences," Bulitt says. "[My school's own] sophomore year's regular physics class -- there was only one level available -- prepared me very well for the [AP] Physics A exam. Ten to 15 of my classmates joined me in taking that test. Chemistry, I took this way as well. Only two of us took this exam, but we both acquitted ourselves well."

A guidance counselor recommended to Luther College sophomore Cavan Krekelberg that he sign up for AP classes when he was in high school. Krekelberg says the chance to obtain college credit was but one of the reasons he did take the AP classes. He also liked the fact that the AP coursework was more challenging.

Krekelberg took three of the four AP classes offered at his public high school in Minnesota. On his AP exams, he received a score of 4 in both psychology and biology, which Luther accepted for credit. His score of 3 on the English literature exam didn't meet Luther's requirements for credit, although some schools do accept 3s.

"If you're toying with the notion of going for an AP class, I say do it," says Krekelberg, a music education major. "It can't really hurt you, as long as you're willing to do the work. Getting college credit from high school classes is invaluable, too."

If you're interested in taking an AP class, try to talk to your guidance counselor about it during your sophomore year or early in your junior year before you select your 11th grade classes.