If I understand it (and I think we've used something like that term in some of our papers), 'jitter' simply means the variation in the latency of the spike evoked by a fixed stimulus (such a a current injection). I'm not sure it means much of anything, but if you want to analyze it, you'd simply measure the latency across multiple trials and apply the same sort of stats that you'd use for anything else.
Here are a couple of papers that may be of use……one more general for spike train analysis: http://papers.klab.caltech.edu/255/1/259.pdf and one that specifically mentions jitter: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2782407/