What version of FileMaker do I need to use NinjaCal
NinjaCal requires FileMaker 9 or higher and is completely compatible with FileMaker Pro 10. If you don't yet have a copy you can download a trial here: http://www.filemakertrial.com
NinjaCal's calendar widget is developed entirely with native FileMaker 9 elements. There are no plugins or custom functions used. All effects are accomplished through the judicious use of conditional formatting and calculations.
Does NinjaCal work with Instant Web Publishing?
Unfortunately, no. (You already knew that, didn't you?)