The Dell/Ubuntu deal is mentioned in this weeks Ubuntu Weekly News digest (which you can subscribe to via here).
Here's what they say about it:
The long awaited release of Dell computers preinstalled with Ubuntu was this week, with Dell announcing three different models, two desktops and one laptop. All three laptops contain mostly Intel parts, with the two desktops using Core 2 Duos. All models are priced about $50 USD cheaper than the equivalent Vista models. Currently they only available in the US, although Dell representatives in at least Canada and Australia have confirmed that they will be available in those countries. You can see more at http://www.ubuntu.com/dell and you can purchase the models at http://www.dell.com/open