I haven't taken AUD yet, just started wiyh studying for REG 2 weeks ago. I bought a self study review course with Yaeger, which uses wiley textbook. There are several courses out there that seem good. I learned a lot about the whole process by reading blogs such as another71.com, ipassthecpaexam.com
Which books are you following? Can u also assist me with preparation. I have done ACCA from Uk but I moved California last year so I guess CPA is better here. Have u started audit yet ?
And good luck for ur prep.