Ada

Here are some links about Ada:

Ada is the only language with an official validation suite. This site also contains the standard and a database of issues with the standard.
Ada Power is currently the most active and interresting site about Ada.
Ada IC.
Gnat is an Ada compiler freely available. Supoort is available from ACT. It is now integrated into gcc, the compilers suite of project GNU.
Ada Home was an interesting site which is no more maintened. It still contain valid information but pay attention as some is obsolete.