I would usually look here, when I didn't have a particular place in mind, and actually, a quick search (limiting to part-time) turns up a part time job at the rare books library at Harvard wanting someone to update Wikipedia pages on topics relevant to Houghton collections, which could be right up your alley. It's a three month term position, but it would get you library experience, and it looks like you can work any schedule while they're open. At Houghton!