Update status: The latest version of Lertap 5 is 22.214.171.124, released 12 December 2018.
The "Useful links" found further down the page do these things:
(1) takes you to the downloads page for all versions, Windows and Mac
(2) links to webpages describing how to upgrade Lertap so that it is not restricted to 100 data records.
(3) links to the "updates summary" for all versions of Lertap.
(4) links out to a website with sample datasets.
(5) will take you to a website with some very practical pointers on using Excel and Lertap (includes numerous examples of Lertap and Excel in action).
(6) and (7) are instructive YouTube videos about Lertap, produced by Tony Davidson.
(8) has RMCS lecture notes used by Larry Nelson in the year 2018
(9) links to RMCS class references used by Larry Nelson in the year 2018
(10) and (11) go to examples of IRT analyses using R packages
(12) a polytomous IRT example for use with RStudio; uses data from the BFI-25 study
(13) links to an R script that will install the packages used by special Lertap macros, such as 'Omega1'
(14) links to a copy of the FIMs original Lertap workbook
(98) takes you out to the Lertap 5 e-store