Bukkit

1 - Make sure you set Events.PlayerMove to true at config.yml. [You need to restart the server to active this function, sorry]

2 - Select the area with the yellow stick [blaze rod?]
2.1 - You can use /cc sel expand [up/down/ver] <amount> to expand the selection!

3 - With the area selected type: /cc region define [survival/creative] [regionName]

4 - Done!

To delete the region, just type /cc region remove [regionName]