You can distribute GPL'ed code in binary form, you just have to make the sources available as well. And, yes I would use this as a test: if your program needs gpl-ed code for some of it's functionality, you have to licence your program according to the GPL - unless you distribute the GPL'ed parts separately and your program is still basically functioning without the GPL'ed code.
Now, if you are unsure about these questions and are serious about writing a program using GPL'ed code, the FSF is probably willing to help you with your questions. Besides this, why not putting your code under the GPL? - Josef -- http://mail.python.org/mailman/listinfo/python-list
