Posting rights , newbie question, how to make new users subscribers by default?

Hi,

I would like for noone to be able to post to my site unless approved by me first. That is, I’d like new users to be given the role of “subscriber” by default.

The wordpress codex says: “The default role for new users can be set in Administration Panels > Settings > General.” but I can’t see anywhere in the general panel that lets me do this.

I know this is a newbie question but I am stuck having read the codex and I would be very grateful for any suggestions that could help me fix this!
Is the problem perhaps that my site is a free one hosted by wordpress (the address is http://southerncrossclub.wordpress.com/)?