ok and the macbook?
and if lets say i have installed a program for instance itunes on computer "A" with the user "josh"
if i go to computer "B" and log in with "josh" will i still be able to use the program.
and for the 3 laptops that are around how will they connect.
Programs (for the most part) do not roam with a user in an active directory environment. Some small ones (portable apps) could be made to do so - although since you would have to download and upload those files each logon/logoff - there is a tradeoff. There are other things you could do with other tools to make this happen, however.
What about the question I asked - what version of Windows 7 do you have on everything? Is it Windows 7 Professional or Ultimate edition (if not - you cannot JOIN an active directory domain.)
The macbook could be made to 'authenticate' off the active directory domain - but it's not going to do all the tricks the WIndows systems will do. Pretty much you get central authentication. ;-)
A windows laptop is no different than a windows desktop as far as Windows itself is concerned. You might have to configure the wireless devices differently (so you can be connected without being logged in) or tweak a few other things - but only because you might be using wireless networking as opposed to wired.