Are there any "ethics" in dating multiple women?

Short background story: the past few days, I was awesome/lucky enough to grab a few phone numbers. I'm interested in dating more than one of them, but since I've never been able to have this kind of opportunity, I don't know too much about what I should/shouldn't be doing.

Is there any advice worth sharing in this department? Aside from the obvious "don't sleep with more than one of them" (since they all know each other and are friends).