this is an extremely broad question. what do you already know? what exactly do you mean by 'analyze'?
as a starting point, i recommend you download the trial version of the product (it's free) and walk through the tutorial--it includes a downloadable data set: http://docs.splunk.com/Documentation/Splunk/6.2.0/SearchTutorial/WelcometotheSearchTutorial
you may be able to ask more targeted questions at that point.