The Montana Republican Party recently decided not to hold a presidential nominating caucus in February 2012. Instead the party will treat its presidential primary in June 2012 as the method for selecting delegates. See this story.
In 2008, the June presidential primary was just a “beauty contest” for Republicans, with no binding force. The 2008 Republican delegates were chosen in a February caucus.
Montana primaries have always been open. Montana has never had registration by party.
The Republicans didn’t like the cost of the caucus since the party paid for this caucus vs having the tax payer pay for the primary. Republicans took notice when the Ron Paul folks were taking over the party. In the end the Republicans used the primary for the presidential delegate count and not the caucus.