First and foremost it will be a great way to spend some quality time with your son or daughter. (Yes boys can work with yarn too!)
Cowls: Now, here is a project that is hotter than hot. Cowls, aka mobius knitting is all the rage right now. And no wonder. These little beauties are attached at their ends when finished and they are also called Infinity scarves. Besides looking just terrific with any wardrobe, cowls are the best warmer-uppers on cold winter days. Easy to knit, they can be finished in a weekend.
Fastenings: Plain flat half-inch buttons are best to use for fastening. Avoid nylon and metal fastenings, as they get very hot under the incubator heaters. Do not use Velcro as a fastening, it is very scratchy on the hook side and also damages knitted garments when they are laundered. Ease of dressing is vital for preemies and as a general rule it is best not to use ribbon as a fastening as ribbon can often be fussy to tie on a garment so small.
Finally, one essential accessory to keep your equipment safe is a set of knitting needle caps, which are designed to be placed over the end of your needles when they are not in use. As mentioned above, needles can cause damage to bags that they are kept in, and can even prove a safety hazard, especially if they fall into the hands of children.
The charities have a lot of information on their websites, below is some general advice to help you get those needles clicking.