First ask the car dealer service department. Then check your local auto parts place such as AutoZone or Oriellys even Napa. These should be able to tell you what not to use. Do make sure you use something that is compatable with alluminim radiators. I think most antifreeze today are.
12-30-08: I do not recommend using DexCool at all. I personally will remove, flush the system, and use an Antifireeze that has the "For all colors of antifreeze" label.
At this time I have not used and am not familure with the G-05 antifreeze.
Personally, I don't like the Dex-Cool antifreeze. I'd just as soon drain, flush, and replace the coolant with the normal green stuff. You just need to change it every other year. I think the orange coolant causes more problems than it solves.
Consider the G-05 that Ford and Chrysler use. It is the result of the hard lessons learned by certain manufacturers with the DexCool™. Prestone's All Makes All Models might also be good - hard to imagine Prestone repeating their mistakes with DexCool™.
G-05 is sold at Chrysler and Ford dealers - Chrysler/Mopar calls it "150,000 Mile Long-Life", Ford calls theirs "Premium Gold". Also, Zerex makes it in aftermarket - just make sure it says it's G-05 on the labeling.
Ford's and Zerex's is bright yellow color, Mopar's is dyed a reddish color looks similar to DexCool™ only not as orange, but it is chemically different from DexCool™ (but same as Ford's and Zerex's G-05), and people do not have problems with it.
FWIW, DexCool™ is called OAT type, G-05 is called HOAT - if you want to do some Google research.