The goal of the IRAM key-project ``Small-scale structure of pre-star forming regions'' is to map three nearby (d~150pc), quiescent molecular clouds with a high angular and spectral resolution to study the molecular cloud structure down to the smallest linear scales currently accessible by single dish radio telescopes. The key-project maps are available as data cubes (velocity, right ascension or galactic longitude, declination or galactic latitude) available as a set of 40 FITS files stored in the fits subdirectory; a summary of these 40 files is contained in the file "list.dat". The observations reported concern the molecular clouds L1512, L134A, and MCLD 123.5+24.9 in the Polaris Flare. The released data set of the IRAM key-project (Falgarone et al., 1998A&A...331..669F) are error beam corrected using the beam pattern parameters published by Garcia-Burillo, Guelin and Cernicharo (1993A&A...274..123G) and observations made with the KOSMA 3m telescope. Bensch et al. (2001A&A...365..275B) present the corrected maps using the 30m beam pattern recently published by Greve et al. (1998A&AS..133..271G). They estimate the accuracy of the maps of the key-project as 10-15% for the CO(2-1), except for two ^13^CO(2-1) maps of the MCLD 123.5+24.9/Polaris Flare and of L1512 where the uncertainties are estimated to 22% and 18% respectively. For the CO(1-0) data, the overall accuracy is 11%.