The seed potatoes that my Mom sent from Oklahoma arrived safely, and I sliced them into egg-sized chunks several days ago. After letting them dry with the cut-sides up, I've turned them eyes-up in a tray to let new sprouts develop in the light.
I know that some people place their cut-spuds in the dark for this chitting. (A little off topic -- even though the word "chit," when used as a verb, refers to the sprouting process generally, I've only ever seen it used with potatoes.)
However, when the sprouts form in the dark, they tend to elongate rapidly and become brittle. As a result, they are very easy to break off accidentally during planting. If the sprouts are formed on potatoes in the light, they are stockier, a beautiful, healthy green, and less likely to get knocked off or broken during planting.
This North Carolina State University fact-sheet on Irish (or white) potatoes includes a helpful illustration and explanation of how to know where to slice seed potatoes to get good pieces for planting, and it also offers the useful reminder to eager gardeners to wait for slightly less-cold weather before planting. Some of the University-originated information published on home garden potatoes use 45 degrees F as the minimum soil temperature for planting seed potatoes, but the NCSU fact sheet suggests waiting for a higher temperature - 50 degrees F.
I probably won't wait quite that long, but today the garden is soggy; we've just had another three inches of rain. It will take a few days for enough of that water to drain away that it will be safe to work in the garden.