The GSEAlm package contains tools for linear-model inference and diagnostics, tailored for Gene Set Enrichment Analysis (GSEA). We demonstrate the package's main features, using the acute lymphoblastic leukemia (ALL) dataset, comparing the BCR/ABL and NEG phenotypes via GSEA based on chromosome-band mapping of genes. If you want to follow the text while running the code, please use the code from the GSEAlm.R le in the same directory where this document is found, because there are some code excerpts which were hidden from view in the tutorial below. A more up-to-date and academically oriented exposition of the tools coded in this package is available at Oron et al. (2008).