The blue tooth version has blue tooth instead of USB. So you will have to use an external power source and a blue tooth dongle for your PC so you can upload your sketches.
Not sure where you purchased it from but from what i see the description at Sparkfun spells it out for you.http://www.sparkfun.com/commerce/product_info.php?products_id=8255
Description: This is the very popular Arduino platform with a Bluetooth® serial connection [glow]in place of the USB[/glow] connection. Now you can have Arduino without wires!
Odd that they describe it that way. An Arduino without wires is a board without a function.
If you wanted Blue tooth and USB you should have gotten the regular Duemilanove and this. http://www.sparkfun.com/commerce/product_info.php?products_id=9358