Greg Reh'm Site has a calculator for wave guide antennas, but I don't know if the background formulas are specific to a 2.4 GHz range.
Putting in a diameter of 1.5" gives you a TE11 of 4611.51 and a TM01 of 6023.23 so it would cover the full range used by 802.11a, unfortunately it doesn't show any of the probe placement or can length information because it falls outside the 2.4 GHz 802.11b ranges.
As I said, I'm not positive the background formulas aren't 2.4 GHz specific, but I don't think they are. I believe they are all standard microwave formulas.
At least it's a starting place.
Linc's software errors out on the probe positioning and can lengths too.