I've got an IP cam (Foscam) set up - ports forwarded so I can access it & view on the WAN. However in doing so I cannot access it via the LAN (I have to type in the external IP address to access the cam). Can I set up the port forwarding so that I can also access it on the LAN to avoid hogging bandwith on the internet connection?

It's not too much of an issue with just one cam but I plan to set up a couple more as part of a home security system.