Confused about the Missouri caucuses today? That's understandable. Missouri already had their 'primary' back in February, which Rick Santorum won, but decided to not have it count or they would have lost half their delegates, according to RNC rules.
That meant they held their caucuses today; but these caucuses don't automatically award delegates. According to the Missouri GOP website, these caucuses are to send representatives to future meetings: Congressional District Conventions (April 21) and State Convention (June 2). According to the website, "Delegates selected at the county level will not be bound to a specific candidate unless a rule is passed by participants of the caucus."
In addition, the Missouri GOP won't be declaring a 'winner' today: "Neither the Missouri GOP nor any election authority will have or release any data regarding a "winner" of the caucuses." It does give information to contact the local committee representatives.
Regardless, this article from the St. Joseph Post online says interest in participation seems to be high among Missourians: "The Missouri Republican Party says a lot of people are asking how to take part in this weekend’s caucuses."
UPDATE: It looks like at least one caucus is going with the binding to a specific candidate. For example, this New York Times article talks about how one caucus voted earlier this week to bind their delegates to the February primary, meaning Santorum picked up 4 more.