I find that most people usually take theirs off next to my shoes that are already at the door. I do try to tell people in advance that I don't wear shoes in the house this way they can plan ahead, and that works too.
Like a couple of other people in this thread, I always answer the door in socks when I know I have people coming over. If you expect your guests to walk around in their socks, you should do the same to set an example.
Overall, you'll find that your house stays much cleaner without shoes, and you'll be a lot more comfortable too. I myself actually just converted not too long ago and after seeing the difference it made, I wish I did it a long time ago. It does take a little while to get used to, but once you get into the habit, it will feel natural to kick them off and go about your day.