Inkle Loom Pattern Generator - using a fill-in form you can try different patterns with lots of colours and see how it will look.
Master Yarn Chart - from Interweave Press; lists many yarns with yards per pound and sett. Free but must register.
Reed Substitution Chart - figure out how to thread the reed when you don't have the most appropriate reed
Treadle Reducer - a simple form that helps you reduce the number of treadles a pattern uses when you don't have enough