In a recent visit to home I was presented with an old problem that had become a real annoyance. The iOS devices owned by the family (minus the iPad) including my iPhone would not connect to the house WiFi network. They would happily detect them but the moment they tried to connect they would time out.
It took a bit of pecking around and trial and error but I found a single change that then allowed all the devices to connect.
It boils down to only allowing 802.11b to operate on the 2.4GHz band instead of the default dual b/n. It see,ms the iPhone and iPod Touch devices do not play nicely with dual use of that band by the b and n standards.