Seeing current permissions for a file?
If you type ls -l in terminal you get the permission for your file

drwxr-xr-x   7 ---  staff   238 Apr 14  2010 images
-rw-r--r--   1 ---  staff  2628 Aug 26  2009 index.html
drwxr-xr-x@ 11 ---  staff   374 Feb 28  2010 simplemvc


You can use table below to convert rwxr-xr-x to number and vice versa:



And get more detail here.