The manuals can be found under the
Information tab under
General at www.iahsaa.org
Here's the link to the 2014 Spring Manual
http://www.iahsaa.org/wp-content/uploads/2014/03/2014_IHSAA_Spring_Manual_Web.pdf
Here's a direct link to the general information page.
http://www.iahsaa.org/information/general/
Be advised, the IAHSAA information can be scattered among their different manuals. For example, while most items related to baseball are in the spring manual, there are some baseball items that are noted in the IAHSAA "Handbook", which is also available on the General page. Also, general information about transfers, eligibility, conduct, etc... are all in the 2013-2014 IAHSAA Handbook.
Finally, at the bottom of the General page, you can access the enrollment lists used for classifications in the various sports. Of course you have to go to Appendix 1 in the Handbook to see how classes are assigned in each sport, I mean, why make it easy and put the information in one place? For anyone interested, I think they already have the enrollment numbers used to classify schools for the 2014-2015 school year posted.
I know this is more than you asked for, but I thought I'd share what I'd discovered out there.