http://math-atlas.sourceforge.net/The ATLAS (Automatically Tuned Linear Algebra Software) project is an ongoing research effort focusing on applying empirical techniques in order to provide portable performance. At present, it provides C and Fortran77 interfaces to a portably efficient BLAS implementation, as well as a few routines from LAPACK.
If you download the software, it is critically important that you check the ATLAS errata file. This file lists all known errors in ATLAS, and all known system problems (eg., compiler errors, etc), and any fixes and workarounds.
See the faq for support help.
The newest ATLAS papers can be found here.