Simple way to link things anywhere on the image. This is good if you want to have a navigation bar without having too many slices.

You will need to find out the coordinates by opening Adobe and using the Info window.
go to window > Info

Okay here is the code.

Add this before the Image code.

Code:
<MAP name='mapname'>
 * * * * <area shape='rect' coords='topleft,corner,lowerright,corner' href='src.htm' target='_new'>
 * * * * <area shape='rect' coords='topleft,corner,lowerright,corner' href='src.htm'>
 * * * * <area shape='rect' coords='topleft,corner,lowerright,corner' href='src.htm'>
 * * * * </MAP>
topleft,corner = x,y
lowerright,corner= x,y

dont use spaces to seperate them.
Note: Only use the target code if you plan on directing that link to a frame.

Next comes the image that will be used with this map.

Code:
<img src='image.jpg' width='size' height='size' usemap='#mapname'>
It is important that you put the # before the map name. If it doesn't have it, it wont work. also make sure the width and height of the image are exact, this makes it easier for the mapping to work. Another thing, capitalization does matter. so MapName is not the same as mapname.

Let me know how you like it ! (= or if something isn't right let me know also !

Edit: Finally worked on an example, Hopefully crofty doesn't mind me using his render for this example.
Example

-sh4d0w