iPhone and wifi

I can't figure this out. Maybe someone else has had the problem. I can't connect to anything over wifi in my house. Safari, app store, itunes, weather, etc. If I turn off wifi and go to 3G it all works fine. Wifi was working last week, havn't changed anything on my router and im on my iMac right now over wifi. While connected to 3G it says 3G and when I go to wifi it connects and has the status bar in the top left.

Go to settings on iphone. Genral> Reset>Reset Network Settings. This happens to me some times an i do that and it usally works for me.. Or just try to hold the top button while holding the home button until the apple appears and that might do it..

Try reseting the router. This happened to my imac once and i went nuts. finally when i got the people from apple online they told me to reset the router. Fully unplug the router from the wall then plug it back in and power it on.. After these few things i suggested i am out of awnsers good luck..