Two options:
There should be a 'Test' button on the JetDirect (small button in back.) The current IP will be on the second sheet printed.
Of course, if none of the current configuration information is worth keeping, reset the JetDirect. First, unplug the JetDirect's power cable from the back of the JetDirect box. Then hold down the aforementioned 'Test' button while plugging the power back in. Continue to hold the button for about 20 seconds. Resetting the box will automatically set it for DHCP, and the 'Test' button printout will give you the IP for further configuration through the web browser. Note that it usually takes about two minutes for the JetDirect to obtain an IP through DHCP.