Will the WiFly Shield from SparkFun labs be able to connect to a Bluetooth network?
No, definitely not. It connects to WiFi (802.11a/b/g) networks, not Bluetooth (802.15.1).
I don't think an Arduino Bluetooth shield is available commercially today. Your best bet is to either buy an Arduino with Bluetooth integrated or figure out how to connect a USB or RS-232 Bluetooth adapter.
By the way, on behalf of electrical engineers, I apologize for this 802.11.15.1.a.b.g nonsense. Collectively, we're bad at some things, and naming protocols appears to be one of them.