Currency-Rates.com

Enter the amount and see the conversion!
<ul>
<li>Add Smart Currency Converter Widget on your site</li>
<li>Choose from 70+ currencies</li>
<li>Change default currencies from your widget settings</li>
<li>Fast, simple and accurate!</li>
</ul>

Smart Currency Converter

Looks like I'm one of the first ones to get to use it :)

Really easy to use, just drag it to your sidebar and you're good to go! I like the fact that you can simply select the default currency pair, unlike some other plugins.

Works like a charm!

Smart Currency Converter widget enables you to convert between 70+ currencies with the latest exchange rates.

IP2Location

IP2Currency Converter provides you a nice and ready-to-use widget to easily add the currency exchange rate function into your website. Below are the features: 
– Support up to 58 commonly used currencies 
– Daily updated exchange rate 
– Customizable style, e.g, the color and skin.
Note: Your will need to register a free API key to gain access as the convertion results are calculated on IP2Currency server.

IP2CurrencyConverter

Add this widget at your sidebar to display a currency converter.

Smart Currency Converter vs IP2CurrencyConverter