The National Institute of Standards and Technology is recommending that touchscreen voting machines be decertified for 2007:
One conclusion drawn by NIST is that the lack of an independent audit capability in DRE voting systems is one of the main reasons behind continued questions about voting system security and diminished public confidence in elections. NIST does not know how to write testable requirements to make DREs secure, and NIST’s recommendation to the STS is that the DRE in practical terms cannot be made secure.
The same article notes that Cuyahoga County, Ohio, is considering scrapping their machines outright. Excellent news for Ohio voters.