IDPA HQ has implemented an official list of the rules clarifications and changes on their website, which is a great help to small clubs trying to use identical rules to state and national matches.
http://www.idpa.com/Documents/RuleAddendum_07062010.pdf
From HQ IDPA:
We have created an addendum to the IDPA rule book. These rule addendums are an important part in clarifying the rule book and help in keeping IDPA headed in the right direction. Some of what is listed is simple clarifications but there are several rule changes as well. Most of these items will be of real benefit to our members such as increased weight limits for CDP and additions to the inclusive list of permitted modifications. The addendum can be found on the IDPA website or on the new forum. The forum will be a great place to let us know how you feel about this addendum. This rule addendum will go into effect on August 1st.
http://www.idpa.com/Documents/RuleAddendum_07062010.pdf
From HQ IDPA:
We have created an addendum to the IDPA rule book. These rule addendums are an important part in clarifying the rule book and help in keeping IDPA headed in the right direction. Some of what is listed is simple clarifications but there are several rule changes as well. Most of these items will be of real benefit to our members such as increased weight limits for CDP and additions to the inclusive list of permitted modifications. The addendum can be found on the IDPA website or on the new forum. The forum will be a great place to let us know how you feel about this addendum. This rule addendum will go into effect on August 1st.