There are some Viewers that can be used to import and export objects.
To share, Export the object as shown on the first picture.
Export the scripts, animations or sounds manualy.
Scripts you can open in the viewer and select the text, copy paste it to a textfile on your desktop.
Animations or sounds can not be exported (yet) so you need to be the owner and have them on your computer.
Sounds you can find in the cashe of your viewer (this is not an oficial way of exporting)
Put the whole folder compressed on a server (ubuntu one is handy). Place here the link.
To Import an item. Download it from here. Import the XML as shown on the next picture.
Place the LSL scripts, animations and sounds manualy. Scripts by creating a new script in your inventory, copy pasting the script from your desktop to the newly created script. Save the script and place it in the object. Animations and Sounds can be imported using the viewer import menu.
more on how to import and export: Content_Backup
list of items:
list of places where to find more free lisenced items: