I just read "Perfect Personal Statements" by Arco. It was an old edition (1995) but very informative and it catered to personal statements for graduate programs. For example, for med school, business school, law school and general masters degrees. It provided 30 actual examples of personal statements that were successful in gaining entrance for those applicants. Negative: there were no examples for CRNA applicants, but the general principles that the book talked about were applicable and helpful. It definitely helped me to write my personal statement. I would really suggest getting started early and then submitting it to several friends for their input and suggestions for changes. Keep revising until it is just what you want.
Hope this helps.