I'm using a wrapper class on the Case object so that users can select multiple users to "tie" them to a case.  Upon selection, these additional users are inserted into the Case_Associate__c object, which is a detail to the Case.  

Here is a link to the full code: http://boards.developerforce.com/t5/Apex-Code-Development/Test-Method-to-cover-Wrapper-Class-only-covering-79/m-p/364981

How can I check to see if a record has already been created in the Case_Assoicate object in my Apex class, before inserting, to avoid duplicate Case Associate records that include the same case ID and user ID?  Below is the code snippet I need to expand on:

Thanks for any help!

public PageReference processSelected() {

//We create a new list of Users that we be populated only with Users if they are selected

List<User> selectedUsers = new List<User>();
List<Case_Associate__c> caseAss = new List<Case_Associate__c>();  //here is where I list out the records to set it up to check for dupes before inserting

//We will cycle through our list of cUsers and will check to see if the selected property is set to true, if it is we add the User to the selectedUsers list

for(cUser cUse: getUsers()) { 
if(cUse.selected == true && User.Id != Case_Associate__c.User.Id) {  // check for duplicates on the Case Associate object before adding the Users to the selectedUsers list
selectedUsers.add(cUse.use);
}
}