Optimizing wireless router speed and minimizing interference

"About which channel to use, the book ""Wireless network coexistence"" by Robert Morrow has this to say:

In north America, a non-overlapping
set consisting of channels 1,6, and 11
or an overlapping set composed of
channels 1, 3 5. 7, 9, and 11, can be
selected. The corresponding sets in
Europe are channels 1, 3, 5, 7, 9, and
11, can be selected.

To detect interference, you might use a WiFi finder to map out your environment.
This article discusses several such utilities."

as far as finding a clear channel, you can use wifi analyzer which is a free app for android powered smart phones with wifi. it's an easy to use app that shows all networks in range, what channel they are on and rates the channels from best to worst according to how much traffic/interference is on that channel. granted it's not a rf spectrum analyzer scanning for interference from other, non-wifi sources such as microwaves and telephones/cellphones; however it works for low level tweaks. they may have something similar for the iphone or other phones but definitely something to look into if you have a smartphone with wifi built in and still having this issue after over a year ;-P just love to bump. and the bean can works, i have been trying to style and fabricate a cone shaped directional antenna so it would cover a wider area but so far haven't found a solution.