Yes you can! This saves time if you want to list a similar item to one that you've already listed.
Once you have created a listing you can copy that listing from the 'Manage Listings' screen. To get to the Manage Listings screen, select 'Your Shop' > 'Dashboard' from the menu at the top of the page, and then click 'listings' on the left hand side. You should see a list of your listings, with a copy link alongside each one.
You will be able to edit all the details of the listing before you publish it.