I tried one of those power inverters and it didn't work with my laptop on an AA 757. I've been using this thing for the past 2 years http://www.tigerdirect.com/applicati...1533&CatId=237 I didn't buy mine at Tiger Direct so I have no comment on their service. Just found the link when I searched for the gadget online.

Unlike an igo, it does not replace your power cord, so you'll have a little pile of cords at your feet. But it works flawlessly and is almost as cheap as the inverter you're considering