The Jackson Laboratory: http://jaxmice.jax.org/
Charles River Laboratories: http://www.criver.com/en-US/Pages/home.aspx
Harlan Laboratories: http://www.harlan.com/
Knockout Mouse Project (KOMP) Repository: http://www.komp.org/
The European Conditional Mouse Mutagenesis Program (EUCOMM): http://www.knockoutmouse.org/about/eucomm