Does anyone know where I can get the maps from hl2?
download GCFScape, open the folder in your Steamapps folder
The .BSPs are in your Steamapps folder in a file called half-life 2 content.gcf
Download GCFScape and you can open the GCFs. With GCFScape you can extract the maps.
You can get them if you load Hammer with the Half Life 2 engine.