To put it in English equivalent terms, while this doesn't exactly match up, it's fairly close:

-San: Mr., Mrs. or Ms. A semi-formal way of showing respect to someone slightly above your station/age.

-Chan, -Kun: Less-formal, sometimes affectionate address for those your age or younger.
(Note: Lee graduated from the academy, and is one year older than Sakura, hence Lee-san. Sasuke is roughly the same age as Sakura and graduated from the same class in the academy, hence Sasuke-kun. This is a way for her to be more flirty/affectionate/respectful with Sasuke-kun than with Naruto, who she doesn't give a title to.)

-Sama: Like "Lord" or "Lady" or "Sir." For someone much higher in rank than you, or deserving of a special honor due to being a religious figure (a priest or miko).

-Sensei: A teacher, martial arts instructor or sometimes can be used to address a doctor.

-Sempai: This is mostly used in martial arts and sports, but I've seen it used in the workplace as well. It's the term for a student who has more experience than you, but is still a student and not at the teacher's level. Might be the captain of your sports team, the longest-term student in the dojo, or the person who's got seniority above you in your job.