Hi Nathan. No jumpers required with that shield. That shield should plug in as-is.
The ethernet w5100 SPI Slave Select is digital pin 10. HIGH is disabled. LOW is enabled.
The microSD SPI slave select is digital pin 4. HIGH is disabled. LOW is enabled.
To communicate with the SD card, disable the w5100 SPI (pin 10 HIGH) and enable SD SPI (pin 4 LOW).
To communicate with the w5100 ethernet IC, disable SD SPI (pin 4 HIGH) and enable the w5100 SPI (pin 10 LOW).
I always disable one, then enable the other. That is just me...
Add: If you plan on using the V1.0 ethernet library, take a look at this post.
http://arduino.cc/forum/index.php/topic,86729.0.html
If you are using Windows, just the web server code will apply to you. I think only Linux GCC has problems with the w5100.h bug.