like everyone stated, it depends on which ibook you have and when it was released.
the late 2004 ibooks and before you can use iscroll2 0.29 with leopard. you get two finger scroll with a quirky way to right click.its still a little buggy about loading but you can go through the iscroll forums and lean how to fix it. it runs fine on my 1.33ghz 14" ibook(late 2004) now.
http://iscroll2.sourceforge.net/#status
also for right click, you can use one finger snap instead, just hold down the click button for 0.5 secs and you get right click. this also works for the regular one button mac mice. i also like this solution better than the right click solution in iscroll2.
http://www.old-jewel.com/onefingersnap/index.html
i use two together to get both two finger scroll and right clicking. they work great together on leopard and i have total control over my trackpad like having a 3button mouse.
now if you have the last edition of the ibook (mid 2005) i believe if you install leopard it will allow for you to have two finger scroll as a default.
it seems like apple changed the trackpad between 2004 and 2005 versions.
and iscroll2 will not install on the 2005 ibooks. i am not sure about two finger tapping. if it doesnt work i am sure you can isntall one finger snap.
good luck