They are in your cstrike folder.
If you have Steam they are in the cstrike folder INSIDE your Counter-Strike.gcf
For some maps the textures are inside the .BSP, which is in your cstrike/maps folder.
If you have Steam that would be in the cstrike/maps folder INSIDE your Counter-Strike.gcf
Once you have the .BSP, you need to use a program called Textract
to extract the .WAD from it. <<Link coming soon>>
To open Steam Gcache files use GCFScape: