My method is very similar to the Militant Spud's.
The bikes have their own cleaning bucket and rags. Warm water and (blue) Dawn on everything. Then the chain and cassette go in the bucket with some Simple Green Automotive Degreaser diluted with water 8:1. (The one-gallon size costs $10 at Auto Zone and lasts me about two years.) Scrub, rinse, dry them on the radiator. Meanwhile, the bikes get wiped-down with Pedro's Bike Lust.
If the shower is clean, nothing from the bikes sticks. The grease and dirt
will stick to soap scum, so I usually clean the tub first. However, with a wife and kids, you'll have to clean the tub last.
The bikes are stoked, BTW, that this weekend is their mid-winter desalination and spa treatment.
As for routine cleaning, they get hosed-down after every messy ride before being hung on their hooks in the living room. Twice a week the chains are wiped-down and relubed.