How do I style (css) radio buttons and labels?

The first part of your question can be solved with just HTML & CSS; you’ll need to use Javascript for the second part.

Getting the Label Near the Radio Button

I’m not sure what you mean by “next to”: on the same line and near, or on separate lines? If you want all of the radio buttons on the same line, just use margins to push them apart. If you want each of them on their own line, you have two options (unless you want to venture into float: territory):

• Use <br />s to split the options apart and some CSS to vertically align them:

<style type="text/css">
    .input input
    {
        width: 20px;
    }
</style>
<div class="input radio">
    <fieldset>
        <legend>What color is the sky?</legend>
        <input type="hidden" name="data[Submit][question]" value="" id="SubmitQuestion" />

        <input type="radio" name="data[Submit][question]" id="SubmitQuestion1" value="1"  />
        <label for="SubmitQuestion1">A strange radient green.</label>
        <br />
        <input type="radio" name="data[Submit][question]" id="SubmitQuestion2" value="2"  />
        <label for="SubmitQuestion2">A dark gloomy orange</label>
        <br />
        <input type="radio" name="data[Submit][question]" id="SubmitQuestion3" value="3"  />
        <label for="SubmitQuestion3">A perfect glittering blue</label>
    </fieldset>
</div>

• Follow A List Apart‘s article: Prettier Accessible Forms

Applying a Style to the Currently Selected Label + Radio Button

Styling the <label> is why you’ll need to resort to Javascript. A library like jQuery
is perfect for this:

<style type="text/css">
    .input label.focused
    {
        background-color: #EEEEEE;
        font-style: italic;
    }
</style>
<script type="text/javascript" src="https://stackoverflow.com/questions/43643/jquery.js"></script>
<script type="text/javascript">
    $(document).ready(function() {
        $('.input :radio').focus(updateSelectedStyle);
        $('.input :radio').blur(updateSelectedStyle);
        $('.input :radio').change(updateSelectedStyle);
    })

    function updateSelectedStyle() {
        $('.input :radio').removeClass('focused').next().removeClass('focused');
        $('.input :radio:checked').addClass('focused').next().addClass('focused');
    }
</script>

The focus and blur hooks are needed to make this work in IE.