The jQuery validation plugin is an excellent tool for validating forms. The online documentation is actually quite extensive, but I found it difficult to locate any example code that really showed a full implementation of the plugin with all of its methods. After a lot of collaborative work, I've written an implementation of this plugin that manages to use most of the of customizable methods. There's a bit of my own jQuery thrown in this, but it should help to provide others with a good working model that can easily be reverse-engineered.

var cgre = "Required"; //define alternate error message for required fields

jQuery(document).ready(function(){

//format inputs
jQuery('input[type="radio"]').addClass('radio-input');
jQuery('input').wrap('<span class="input-wrapper" />');

/* **
/*  FORM VALIDATION
 */

//define a new validation method for prepopulated fields-- make sure that they haven't been left with default values. this works in tandem with check for 'required' class
jQuery.validator.addMethod("prepopulatedVal", 

  function(value, element, param) {
   if(jQuery(param).length == 1) {
      return value != jQuery(element).attr('rel'); //does it have its default value?
   } else {
    return true;
   }
  },"Please fill out this field."

); 

jQuery("#myform").validate({
 //set custom placement of error messages. do not modify css information here (do that in the 'highlight' method), only placement.
  errorPlacement: function(error, element) {

    if ( element.is(":radio") ){
      error.insertBefore( element.parents('.radio-wrapper') );       
    }
    else if ( element.is(":checkbox") ){
      error.insertBefore( element.parent().children('input:first') );        
    }
    else if ( element.is("textarea")){
      error.insertBefore ( element );    
    }
    else {
      error.appendTo( element.parent() );
    }
  },
  //set custom error messages
  invalidHandler: function(e, validator) {
    var errors = validator.numberOfInvalids();
    if (errors) {
      var message = errors == 1
        ? 'One required field was left empty. Please complete the highlighted required field, and then click on Submit.'
        : '' + errors + ' fields were left empty. Please complete the highlighted required fields, and then click on Submit.';
      
      alert(message);
    }
  },
  
 
  //define dependency and requirement rules
  rules: {

    media_name: {                   
      prepopulatedVal: '#fee_status_media:checked' //run 'prepopulatedVal' method on media_name only if fee_status_media is checked
    },       
    contact_email: {          
      email: true
    },      
    preferred_format: {
      required: '#have_preferred_format_yes:checked'
    },   
    preferred_other: {
      required: '#preferred_format_other:checked'
    }, 
    explain_contents: {
      maxlength: 3000
    },
    disseminate_to_whom: {
      maxlength: 3000
    }
          
  },
  
  //modify error message for specific input fields
  messages: {
    contact_name: {
      required: cgre //display cgre error message is 'required' validation fails
      //cgre was variable defined earlier as "Required"
    },
    contact_street: {
      required: cgre
    },
    media_name: {
      prepopulatedVal: ''  //display no error message is 'prepoulatedVal' validation fails
    }

  },
  
  //modify input appearance for fields that have failed validation
  highlight: function(element, errorClass, validClass) {
    
    //specific styling for radio inputs
    if ( jQuery(element).is(":radio") ){        
      jQuery('label[for="' + jQuery(element).attr('name') + '"]').addClass('radio-error');   //this will apply the style to all radio inputs that have the same name
      jQuery('input[name="'+jQuery(element).attr('name')+']"').parents('.radio-wrapper').addClass('error-wrapper');        
    }
    //default functionality
    jQuery(element).addClass(errorClass).removeClass(validClass);
  },
  
  //reverse modifications to input appearance for fields that have failed validation
  unhighlight: function(element, errorClass, validClass) {
    
    if ( jQuery(element).is(":radio") ){
      jQuery('input[name="'+jQuery(element).attr('name')+'"]').parents('.radio-wrapper').removeClass('error-wrapper');
    }
    
    //default functionality
    jQuery(element).removeClass(errorClass).addClass(validClass); 
  }    
  //,debug: true //prevents form from actually being submitted

});


/* **
/* END FORM VALIDATION
 */

//force validation to occur whenever fee_status is changed. I've added this here because media_name relies on fee_status for validation, and I want them to be validated together and on-the-fly
jQuery('input[name="fee_status"]').click(function(){
    jQuery('input[name="media_name"]').valid();
});
   

/* **
/* PREPOPULATE FIELDS
 */  

//prepopulate fields that need default values (using rel attribute)
jQuery('.prepopulate').each(function(){
  jQuery(this).val( jQuery(this).attr('rel') );
});

//clear default value on click
jQuery('.prepopulate').focus( function(){
  if( jQuery(this).val() == jQuery(this).attr('rel') ){
    jQuery(this).val(''); 
  }
});   

//restore default value if field is left blank after click
jQuery('.prepopulate').blur(function(){
  if( jQuery(this).val() =='' ){
    jQuery(this).val( jQuery(this).attr('rel') ); 
    jQuery(this).valid(); //check validation on this field on blur
  }
});

/* **
/* END PREPOPULATE FIELDS
 */      

});