Like Craft, Knowledge, and Profession, Perform is actually a number of separate skills.
You could have several Perform skills, each with its own ranks, each purchased as a separate skill.
Each of the nine categories of the Perform skill includes a variety of methods, instruments, or techniques, a small list of which is provided for each category below.
You can impress audiences with your talent and skill.
A masterwork musical instrument gives you a +2 circumstance bonus on Perform checks that involve its use.
Action: Varies. Trying to earn money by playing in public requires anywhere from an evening's work to a full day's performance. The bard's special Perform-based abilities are described in that class's description.
Try Again: Yes. Retries are allowed, but they don't negate previous failures, and an audience that has been unimpressed in the past is likely to be prejudiced against future performances. (Increase the DC by 2 for each previous failure.)
Special: A bard must have at least 3 ranks in a Perform skill to inspire courage in his allies, or to use his countersong or his fascinate ability. A bard needs 6 ranks in a Perform skill to inspire competence, 9 ranks to use his suggestion ability, 12 ranks to inspire greatness, 15 ranks to use his song of freedom ability, 18 ranks to inspire heroics, and 21 ranks to use his mass suggestion ability. See Bardic Music in the bard class description.
In addition to using the Perform skill, you can entertain people with sleight of hand, tumbling, tightrope walking, and spells (especially illusions).
The character can sway an audience's attitude with his or her performance.
Fanatic: In addition to the obvious effects, any NPC whose attitude is fanatic gains a +2 morale bonus to Strength and Constitution scores, a +1 morale bonus on Will saves, and a -1 penalty to AC whenever fighting for the character or his or her cause. This attitude will remain for one day plus one day per point of the character's Charisma bonus, at which point the NPC's attitude will revert to its original attitude (or indifferent, if no attitude is specified).
Treat the fanatic attitude as a mind-affecting enchantment effect for purposes of immunity, save bonuses, or being detected by the Sense Motive skill. Since it is nonmagical, it can't be dispelled; however, any effect that suppresses or counters mind-affecting effects will affect it normally. A fanatic NPC's attitude can't be further adjusted by the use of skills.
Source: SRD 3.5 Combined Skills