A three-tier architecture looks like this:
>
>Tier 1: User Interface, Application logic
>Tier 2: Business objects / rules
>Tier 3: Data
>
Like Paul, I have also been trying to get an handle on this style of development for a while now as well. Unfortunately I haven't had any small apps to write where I could afford to really experiment, they've all been big, mission critical systems. This has meant that I've had to take on small step at a time.

In my current phase of development, I have a series of classes, based on a container, and each of these classes has the functionality within itself to know how to manage something or do something.

e.g. I have one called bizFindCustomer, which contains the functionality to allow the user to find and select a customer, whose ID it stores in an exposed property, for other objects to pick up. This object contains controls to allow the user to find the customer he/she wants i.e. a drop-down listbox to pick a search item, a textbox to key in search text and a listbox to display search results. Given that these are all part of the UI, is this a business object?

If not, could anyone tell me what a true business object would be like for this particular example??