Comment puis-je intégrer des icônes Font Awesome dans un champ de saisie de texte ?

<input name="txtName">

.errspan {
    float: right;
    margin-right: 6px;
    margin-top: -20px;
    position: relative;
    z-index: 2;
    color: red;
}

<div class="input-wrapper">
     <input type="text" />
</div>

.input-wrapper {
    display:inline-block;
    position: relative
}
.input-wrapper:after {
    font-family: 'FontAwesome';
    content: '\f274';
    position: absolute;
    right: 6px;
}

@font-face {
     font-family: 'FontAwesome';
     src: url('../Font/fontawesome-webfont.eot?v=3.2.1');
     src: url('../Font/fontawesome-webfont.eot?#iefix&v=3.2.1') format('embedded-opentype'), url('../Font/fontawesome-webfont.woff?v=3.2.1') format('woff'), url('../Font/fontawesome-webfont.ttf?v=3.2.1') format('truetype'), url('../Font/fontawesome-webfont.svg#fontawesomeregular?v=3.2.1') format('svg');
 }