From a post on AAS, Ive used this:
Octro
Signup (free), and install the app.
It can use either a data connection, or Wifi.
Its pretty good, was as slow for me as I have no wifi or 3G here. But it worked.
After signing up, you just send the page link to whoever, with your username, and they can view the cam.
However, its not the sort of thing if you want to have a cam with MSN etc.