yeah, OEM copies of windoze don't cost too much, especially for someone like Dell.
I do, however, think this is big news. For one, with Dell's endorsement of Ubuntu, third party hardware and driver support for it could be strengthened. Also, this is the second major announcement by Dell that directly relates to the Microsoft Vista debacle. First, Dell said it would resume shipping computers with XP if the user so desired:here
Now, they are endorsing the leading open source OS. After trying to get Vista to work well for a couple days, I can honestly say Microsoft deserves all of the bad press they are getting for Vista. I really hope the market can overcome their strong-arm practices and allow some much-needed competition in the OS realm.