The New York Times, Economix Blog, February 18, 2010 by Catherine Rampell
http://economix.blogs.nytimes.com/2010/02/18/inflation-wont-solve-our-debt-problems/
Sudden inflation can only inflate away the debt that is (1) not indexed, the way TIPS are; and (2) not very short term (i.e., not T-bills), so that the interest rates cannot be reset to much higher rates that would compensate for inflation. Also, there is no net gain to inflating away debt held within the government (e.g., the Social Security trust fund, etc.).