Mark Mitchell announced the availability of GCC 4.0.3. He explains, "this release is a bug-fix release for problems in GCC 4.0.2. GCC 4.0.3 contains changes to correct regressions from previous releases, but no new features." GCC 4.0.2 [story] was released nearly 6 months ago in September of 2005. GCC 4.1.0 [story] was released in early March of 2006.
GCC is the GNU Compiler Collection which includes C, C++, Objective-C, Fortran, Java, and Ada compilers. Download GCC 4.0.3 from a gcc.gnu.org mirror.