How to import boat plans (tif images) into autocad??

Here is the story:
1. I have ordered some boat plans (hard copy). Some plans are even 9
feet long.
2. A company has been so kind and scanned all the plans as tif-images.
The scans are exactly 1:1.
3. Somewhere on the internet I have read that you can import a
tif-image, make it as a layer and then draw upon the lines you see from
the image making a real autocad file.
But how can I do that? Do I have to use the imageattach command (I have
Autocad 2004) and then import the image like that? It is EXTREMELY
important that the image stays 1:1 in Autocad. How do I turn the image
into a layer? Maybe someone has some advice? Im still a beginner using
autocad :-)
Reagrds, Lucas Jensen