Otou-san (お父さん): father, or otou-sama (さま?). From chichi (父?).
Oji-san (叔父さん/小父さん/伯父さん 【おじさん】): uncle (or middle-aged gentleman). -san can be replaced by -sama or -chan (ちゃん?).
Ojii-san (お祖父さん/御爺さん/お爺さん/御祖父さん 【おじいさん】): grandpa (or male senior-citizen). -san can be replaced by -sama or -chan.
Okaa-san (お母さん): mother, or okaa-sama. From haha (母?).
Oba-san (伯母さん/小母さん/叔母さん 【おばさん】): aunt (or middle-aged lady). -san can be replaced by -sama or -chan.
Obaa-san (お祖母さん/御祖母さん/御婆さん/お婆さん 【おばあさん】): grandma (or female senior-citizen). -san can be replaced by -sama or -chan.
Onii-san (お兄さん): big brother (or a young gentleman), or onii-sama, or onii-chan. From ani (兄?).
Onee-san (お姉さん): big sister (or a young lady), or onee-sama, or onee-chan. From ane (姉?).
http://en.wikipedia.org/wiki/Japanese_honorifics