Seems to me that Dell's position is a reasonable one. If they choose not to "support" linux installs/software then that just provides an opportunity for others to step up and provide that support. If things go well, Dell could conceivably partner with LinuxGeeks.com (I just made that name up) or whomever, and the need will be met. I guess the other interesting thing would be how agressively Dell will choose to market/advertise their Linux capable boxes. I know a guy at work who just bought an emachines PC for the specific purpose of putting linux on it and getting up to speed. I think a national advertising campaign by Dell centered around Linux might generate a lot of buzz if it was cleverly done (could they use Penguins? Or is that somehow protected?).
I'd much rather be left to choose the distro myself. (Once you've had Slack, you can never go back!) Hardware support is the traditional bugaboo during an installation. If they could help to relieve that headache, then there would be a lot of happy penguin campers out there.
(By the by, my workplace is a all-Dell shop. We use their WinXP boxes and a lot of older Win2k boxes. We're very happy with Dell.)
Last I heard general use of the penguin is not restricted, although individual drawings/renderings of Tux are of course protected by copyright. "Linux" is trademarked by Linus for operating systems, and usage of the trademark is governed and licensed through the Linux Mark Institute.