You are taking your laptop with you aren't you?
Assuming you are - when you get where you're going use the control panel and look at network connections - Right Click on the Wireless Logo and select View Available Wireless Connections.
If there are no wireless network connections you're scuppered. If there are wireless connections within range you need to select the one you want. Little green bars tell you the signal strength and some may be Security Enabled. Try it at home first.
I think it may be illegal to attach to a network without permission.
Peccavi
January 2009