GeoTargeted AdWords Preview Tool
Go to www.google.com/adpreview and type in your keyword phrase. If you want to add geo-specific criteria, use the following formulas.
To define the country enter &gl=[Two Letter Country Code Here]
To define the region enter &gr=[region code here]
You can also define city, latitude and longitude, postal code and DMA.
More details at the AdWords Help Center and further explained on the Inside AdWords Blog.