iPhone not working with my Sky Broadband wireless network!! Please help!!

I've just migrated from Tiscali to Sky Broadband, the iPhone worked perfectly with Tiscali but it won't with Sky across the wireless network. I set the new router up (it takes only minutes), and I easily got both iMacs in the house up and running in no time at all. But when I head into the Wi-Fi menu on both my iPhone and my parent's iPod Touch, it keeps saying "Unable to connect". It offers no explanation why, but the network key Sky gives you on a little card (it's either WEP or WPA) is what I am going off to enter the details. I've even tried to manually type the SSID instead of it searching for it, but even that's a no-go. Can anyone help me? I just have no idea what could be doing it. If both Macs work fine, and both Xbox 360s... I don't see why the iPhone shouldn't.