This prototyping shield is the best out there (well, we think so, at least). It works with UNO, NG, Diecimila and Duemilanove Arduinos. You can use it with a Leonardo but it will not break out the hardware SPI pins (they're only on the ISP connector underneath) or the IOREF/SDA/SCL pins. However, the SDA/SCL pins on the Leonardo are also on digital #2 and #3 so you can still use them by connecting to #2 and #3.