I gave my Test 232 just yesterday . The stated passing is 61%
I passed with 78% . The test wasnt all that easy but all I would say is read the 2 Red books on the IBM website. ( PSeries AIX System Admin and PSeries System Support ) and these two together cover about 80% of the course .
You can also read the book ( AIX 5L Administration by Randal Michael ) . It is a good reference book - This covers about remaining 20% .
Rest 5% you will see it on the web if you search for it .