I've separated the window treatment ideas, articles and instructions out the best I could. You'll find some window treatments overlapping from one section to another, and some that may not quite fit the category I put them in.
I have however, tried not to list duplicate window treatment style instructions, unless I thought there was something worth reviewing or that someone else had an interesting way of constructing a window treatment. There are many more articles out there with instructions for making curtains and other decorative ideas. I have basically "cherry picked" the ones that I think are the best, and will be adding to these as times goes on.
So be sure to check back often for the latest! Because "I Do Windows"!
Making wood cornices, upholstered cornices and pelmets.
How to and curtain design ideas for making your own window treatment.
Projects with instructions for making soft top treatments.
Making or embellishing roller shades, romans shades and other shades & blinds.
Ideas for making your own hardware instead of using the traditional methods, along with tips for using the traditional types of hardware.

~ Window Treatment Design Considerations - Form, space, color, balance.
~ Determining Width, Depth & Length of Window Top Treatments
~ Upholstered Shutters - Made from plywood and easy to customize.
~ Faux Leaded Glass - This is so easy. A great way to give you some privacy without covering the window.
~ Make shutters out of old shipping pallets - These have all kinds of possibilities.
~ For some window treatment ideas for kids rooms, check out Decorating Kid Rooms site.
~ Custom Window Fashions Gallery - Gotta go check this out. If this doesn't get you going nothing will! Great design resource.
~ Home Dec in-a-Sec - Design it online. Choose your window treatment style, then your fabric and see how it might look. You can even choose wall color.
~ Drapery Pro - See photos of over 100 custom window treatments made by professionals.