This is a good site to find laptop deals (in fact all sorts of deals)
http://www.hotukdeals.com/
Press the "Filter Deals" button to make sure it updates with the latest deals.
You can also filter by Category, so just select "Computers and Software" to list only those items (you have to press the Filter Deals button again).
This site is updated all the time so revisit a few times a day so you find out the best deals before they sell out.
There is a guy who updates this site with all the lastest Dell deals on a Thursday so make sure you check during Thursday.
(I have no personal interest in this web site, I just find it a very useful site)