After my post on item response theory, a number of you have asked for links to applications that provide R code. As I noted in that post, a good deal of work is being done in an area of research called patient-related outcome measurement (PROM or PROMIS with additional letters for information system). Since that post was published, I have discovered a workshop from The Psychometric Centre at the University of Cambridge. This link takes you to five days of presentation slides beginning with a very basic introduction and carefully moving to applications with R code from several different packages. And while you are there, you ought to check out the other presentations on structural equation modeling, longitudinal modeling, and factorial invariance.
I would be interested to hear what you think of this site. Although psychometrics has made important contributions to statistical thinking and has its own CRAN Task View in R, we do not see many psychometric posts on the blog aggregators. We should change that.