TypeWonder is a useful tool if you want to quickly see what a live site would look like in a different font. Just enter the URL of the target site, then select the font you want to use from the searchable list that pops up. TypeWonder also make it possible to obtain the necessary code for both the HTML markup and the CSS. In addition there are some basic controls over the style and character set.
TypeWonder is especially useful if you want to preview lots of fonts in quick succession, as you can switch from one to the next with just a couple of clicks. This simple functionality alone is great, but you may feel limited by the fact that only one font can be used at any one time – there’s no way to try out font pairs by applying different typefaces to different areas.
If you have need of this service on a regular basis there’s a Chrome extension, which adds the functionality to your toolbar, with Firefox and Safari extensions to follow.
TypeWonder is in beta at the moment and is free to use, so give it a try!