You could also use a **list builder**. (Take a look at "[Designing Interfaces][1]" by [Jenifer Tidwell][2]).

Someone created a [live demo][3] too...  
You can add filters, search and groups to the list on the left, and thus make is easier to "select all" items from a certain group or search result...

![enter image description here][4]


  [1]: http://designinginterfaces.com/
  [2]: http://jtidwell.net/
  [3]: http://www.meadmiracle.com/dlb/DLBPlugin.aspx
  [4]: http://i.stack.imgur.com/I124h.png