Writing a specification

Hey,

I am not a designer but am part of a on going project who is in need of a website.

While i could approach a designer and say i wasnt this, this and this and let him/her get on with it that isnt the approach i want to take and was woundering if anyone had any tips as to what should be included in a Design specification or if anyone had one i could take a look at to get some idea of the format/layout of such a paper.

Many Thanks
Drobbins