And I know labelling boxes is a great idea, but DH found that when it comes to removalists and storage, you are better off getting a notepad, numbering the boxes and then listing what was in the box on the notepad numerically - that way no one else knows whats in it, and you don't have any worries of things going walkabout between your old place and new place. Not saying that all removalists or storage places are dishonest thieves, but there is always the odd chance you cop a bad one.
A spreadsheet works well for this. When ever I need to find something I just ctrl+f, I have a fairly detailed listing, so it is very handy.