Well, DD is getting curious about the bathroom. She's almost 1 1/2, so we're getting close to the start of potty training. I listened up to several suggestions & bought the Tinkle Time Trainer Pattern. I haven't out one together yet, but I've printed out a copy and I'm really impressed with the pattern. The instructions seem clear (after a quick look-through) and the (with the download) the different sizes are in separate PDF files (much easier to navigate & get to print straight).
The pattern is done like most other diaper patterns - the pieces are drawn for cutting on a fold. I plan on printing out mirror-images so I can pin the pattern down on flat fabric instead of wrestling with a fold - this also makes it easier (for me) to lay out multiple copies and do a mass cut-out.