I suggest reading "Indoor Survey", "Mobility Controllers", and "802.11n Networks" VRD's. I read those before attending the Mobility Boot Camp training and felt prepared as most of the content wasn't completely new. Course was a good refresher and a possibility for hands-on training and to ask questions from the trainer. And basic 802.11 knowledge will help also. If you haven't learned 802.11 fundamentals already I would suggest learning at least CWTS level of basics first so you can concentrate on what Aruba brings to the table.
When you get the gear you should learn to setup everything an average enterprise would use. So 802.1x, policies etc.
Check out the study guides if you haven't already:
http://www.arubanetworks.com/pdf/education/SG_ACMA.pdf
http://www.arubanetworks.com/pdf/education/SG_ACMP.pdf
ACMP goes a little further than ACMA but if you feel comfortable with the material and configuration after reading the VRD's and playing around with the gear I'd go straight for ACMP.