Get Source code for my pages

What i am after is a program that can get all the source code from pages on the web e.g. i put in a box [login to view URL] [login to view URL] [login to view URL] could be hundreds or thousands of pages ect I want the program to grab all the source code from each page and save it in an output folder with a choice to have the file as php, html, htm ect any extension i want. Regards Lee