Pinterest is a new social networking site which allows its users to share images in collection with others, currently Pinterest is in roll out process and you may need to wait sometime if you wanna join it.
You can create you collection on any topic like Hobbies, Favorite foods, places you wanna travel and so on, other users you love your collection re-pin it and share it on their page too.
If you wanna share any screenshot of web site or web page then you can use URL2PIN.IT, it allows you to share screenshot of any web page on Pinterest very easily.
To use it, just visit the site and then enter the URL of page or site which screenshot you wanna share :-
Click on Submit button and within few seconds it will generates the screenshot of your web page which can be share on Pinterest :-
After getting your screenshot you just need to click on Pinterest and then login with your account and then enter its description and share it.