Here is the complete package of Black Mesa Songs from Joel Nielsen: BlackMesa-JoelNielsen.zip
This is the sounds for the Intercom which you hear at the start of the tram introduction:
Original: Black Mesa Transit System-Intercom
New: Mesa Lady
And here is a thread from the BlackMesaSource Website that will tell you all about the game (its a long read):
http://forums.blackmesasource.com/showthread.php?s=ae2493bc9a049988d1a0c6adb7c51c23&t=24&highlight=rules+thread
Even as it was said that there will be no Half Life Episode 3 or Half life 2 episode 3 2010, the developers have hinted that 2010 is a possible release for the Black Mesa Mod, because they have actually done quite a lot of work since December last year.
http://twitter.com/BlackMesaDevs
http://www.youtube.com/user/BlackMesaSourceMedia
http://www.catzeyes93.com/images/BlackMesa/index.html
Happy 2010
