You can fully style the button of your choice. In the JQuery File Upload example they have some nice JQuery UI Button style.
<html> <head> <title>jQuery File Upload Example</title> <style type="text/css"> .myfileupload-buttonbar input { position: absolute; top: 0; right: 0; margin: 0; border: solid transparent; border-width: 0 0 100px 200px; opacity: 0.0; filter: alpha(opacity=0); -o-transform: translate(250px, -50px) scale(1); -moz-transform: translate(-300px, 0) scale(4); direction: ltr; cursor: pointer; } .myui-button { position: relative; cursor: pointer; text-align: center; overflow: visible; background-color: red; overflow: hidden; } </style> </head> <body> <div id="fileupload" > <div class="myfileupload-buttonbar "> <label class="myui-button"> <span >Add Files</span> <input id="file" type="file" name="files[]" /> </label> </div> </div> </body> </html>