Since it showed up here and I just found it - the meaning of the letters:
Extraordinary Abilities (Ex): Extraordinary abilities are nonmagical. They are, however, not something that just anyone can do or even learn to do without extensive training. Effects or areas that suppress or negate magic have no effect on extraordinary abilities.
Spell-Like Abilities (Sp): Spell-like abilities, as the name implies, are magical abilities that are very much like spells. Spell-like abilities are subject to spell resistance and dispel magic. They do not function in areas where magic is suppressed or negated (such as an antimagic field). Spell-like abilities can be dispelled but they cannot be counterspelled or used to counterspell.
Supernatural Abilities (Su): Supernatural abilities are magical but not spell-like. Supernatural abilities are not subject to spell resistance and do not function in areas where magic is suppressed or negated (such as an antimagic field). A supernatural ability's effect cannot be dispelled and is not subject to counterspells. See Table: Special Ability Types for a summary of the types of special abilities.
Extraordinary Abilities (Ex): Extraordinary abilities are nonmagical. They are, however, not something that just anyone can do or even learn to do without extensive training. Effects or areas that suppress or negate magic have no effect on extraordinary abilities.
Spell-Like Abilities (Sp): Spell-like abilities, as the name implies, are magical abilities that are very much like spells. Spell-like abilities are subject to spell resistance and dispel magic. They do not function in areas where magic is suppressed or negated (such as an antimagic field). Spell-like abilities can be dispelled but they cannot be counterspelled or used to counterspell.
Supernatural Abilities (Su): Supernatural abilities are magical but not spell-like. Supernatural abilities are not subject to spell resistance and do not function in areas where magic is suppressed or negated (such as an antimagic field). A supernatural ability's effect cannot be dispelled and is not subject to counterspells. See Table: Special Ability Types for a summary of the types of special abilities.