What are those tiny worm-looking things in the the soil I use in my indoor garden, can they hurt my plants?

I noticed after a week or so of planting seeds and they sprout, these microscopic white things start crawling and jumping around in the soil. They kind of freak me out, and I was wondering what they were, what they do, and what can I use to get rid of them? I used a dish soap solution that a friend recommended but that killed my plants as well as the critters.