Affymetrix
Agilent Microarrays and Scanners
GEPAS - Analysis Tools for DNA-arrays
Bioconductor project (an open source and open development computing environment for biologists)
Patrick Brown's lab
The Eisen Lab (free software)
EMBL Expression Profiler
Frontiers in Genomics (educational website)
The Y.F. Leung's Functional Genomics home (very rich website)
Lymphoma/Leukemia Molecular Profiling Project, LLMPP
The Molecular Profiling Initiative (protocols)
NHGRI Microarrays Project (educational website)
R Package
The R Project for Statistical Computing
The Roswell Park Cancer Institute MicroArray and Genomics Facility
The Sanger Institute : The Microarray Facility
Speed's Microarray Homepage
Stanford Microarray Database
TIGR - The Institute for Genomic Research (free software packages)