// add PEAR channel
user@host ~ % pear channel-discover pear.phpunit.de
// install phploc
user@host ~ % pear install phpunit/phploc
// run
user@host ~ % phploc /path/to/your/project/code/folder

For more detailed instructions and system requirements, here is the link.

Now we are going to play a little honesty game:
Run the tool against your php project library code

[user@host] phploc ./library/Zend/
phploc 1.0.0 by Sebastian Bergmann.
Directories: 285
Files: 1372
Lines of Code (LOC): 275436
Comment Lines of Code (CLOC): 130251
Non-Comment Lines of Code (NCLOC): 145185
Interfaces: 53
Classes: 1321
Functions/Methods: 9170

 Run the tool against your php project own code:

[user@host] phploc ./my_application/my_modules/
phploc 1.0.0 by Sebastian Bergmann.
Directories: 30
Files: 85
Lines of Code (LOC): 6644
Comment Lines of Code (CLOC): 580
Non-Comment Lines of Code (NCLOC): 6064
Interfaces: 0
Classes: 94
Functions/Methods: 284

Now calculate the percentage of your code vs. your favorite framework library codepercentage = my_code_NCLOC/my_library_NCLOC*100in my case the result is 4.17% !!! :) How about in your project?