[cjwalkeruk]

This is the reply i got from the service department before i posted the question on here guys:

"This requires modifying the code (i.e., 'hacks', plugins, or template
modifications). We can't offer official support for code modifications or for
forums running modified code. We do however have a customization site and
forums with people that may be willing to help you with this."

Basically it is a standard forum, whereby the admin can post a post asking registered users to register to work by clicking a button on the post.
Depending on how many vacancies are available, this will change the number of buttons in the forum post.
Once a registered user has clicked on the button, the button disappears and is replaced by their username, thereby confirming they want to work. If circumstances change, only admin or the user that registered for work can remove the username and replace it back with a button so other people can register for work.

Hope this makes sense.