iPhone not connecting to linksys wrt160n router

Hello, I just bought an iPhone recently and am experiencing some problems. It connects to wifi at my work just fine, and to wifi at my friend's place; however when I try to connect to the wifi at home it will not connect. I have tried everything; I even turned off the security key to the network so it is now open. When I tell my iPhone to connect to the network, it shows a little tick beside the network name; however the little icon which shows you what network you are attached to still shows 3G rather than the wifi symbol. If I turn it to airplane mode and then manually turn wifi on, I seem to be able to connect to wifi but it is quite slow. Any ideas how to fix this problem? I cannot afford a very data heavy 3G plan so really love the wifi option.

 

Dumb question time:

Did you reset the WiFi router? Unplug it, wait 20-30 sec, plug it back in?

Side question to anyone else:

How do you get McDonald's employees to not look at you like Nipper, the RCA dog, when you ask them to reset their routers?