tangor - 10:20 pm on May 27, 2011 (gmt 0)
You won't get turn key copy paste solutions here unless you've got some concept code you've attempted first...
Best friends... and YOUR list of who you want to let in for fun and games at your website... that list will be different for every webmaster.
(edit) What works for US sites will be different from UK, RU, CN, etc. This forum is international in scope so posting "use this code" to "accomplish this" may not work for all.