Durham University Institute of Plant and Microbial Sciences
http://www.dur.ac.uk/biological.sciences/research/ipms/

Nottingham Arabidopsis Stock Centre
http://arabidopsis.info/InfoPages?template=about_nasc;web_section=arabidopsis

The Arabidopsis Information Resource
http://www.arabidopsis.org/index.jsp

GARNet (Genomic Arabidopsis Resource Network)
http://garnet.arabidopsis.org.uk