I've got a wireless D-Link router provided by my isp with 4 ports on the back. It seems like the devices connect to the physical ports are unable to see any devices that are wirelessly connected. Is this normal? What would the recommended practice be to allow communication between all my devices?
Usually wireless clients can see wired clients and vice-versa. Did you look at the settings on your router?
What exactly do you mean by "see"? Do you know which service discovery/browsing protocol you were trying to use to see the other devices?
What IP address, router address, and subnet mask does the wired device get? What about the wireless device? Can you ping from the wired device to the wireless device (and vice-versa) by IP address?
Do all of these devices have connectivity to the Internet, just not each other?
What wireless security mode are you using? Just as a test, does the problem go away if you turn wireless security off?