Car Adapter Question

[Tbone]

So in two or three months I will start spending a lot of time on the road. I'll be taking my laptop with me, and there's the possibility of using Sprint's network to connect wirelessly to the internet. My other concern is getting power to my Dell M1710 XPS. I've looked around for car adapters, but Dell doesn't seem to make one for my model. The only thing I can find are eBay and other sites claiming to have a car adapter for my model. Can someone take a look at these and see if they will actually work?

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=200123345141&ih=010&category=60252&rd=1&ssPageName=mem_guide:4

http://cgi.ebay.com/AUTO-ADAPTER-FOR-DELL-INSPIRON-6400-9400-XPS-M1710-M170_W0QQitemZ200122479407QQihZ010QQcategoryZ42165QQrdZ1QQssPageNameZWD1VQQcmdZViewItem

http://www.shoplaptop.net/aucarpoadfor2249.html

[Avzeke (Khr0n1k)]

The first one is just a simple power converter, just go to some store and buy a power converter all it is, is just a simple outlet that goes into the cigarette lighter. I took one of those for our trip to DC and it works just fine, it wasn't that same one though.