In JSTOR's last incarnation, you could save citations to your MyJSTOR account and export them to your heart's content. We've recently developed My Lists, an evolving feature that allows you to save citations, export them and organize them into personalized lists. You're probably all like:
How to Use My Lists:
After you make a MyJSTOR account, log in and go to the top left-hand corner of the page. The fourth option from the left is the 'MyJSTOR' tab. You'll want to select the second 'My Lists' option.
Once you're at the 'My Lists' page, find the link in the center of the page (to the right of the menu that includes 'My Profile, My Lists, Shelf, etc) that says 'Create new list.'
Once you select that link, you'll be prompted to name your new list. After you think of a name, click 'Create.'
Now that you've created a list, you'll probably want to search for articles to add to it. You can search straight from the bottom of your list (there's a basic search box there) OR you can go to advanced search. Once you've found an article you want, select the button to the right of your search result labelled 'Add To My Lists.'
After you select 'Add To My Lists' you'll be presented with a window. The window will show you all the lists you've created. Check the checkbox next to the list you want the citation to be saved under. When you go back to 'My Lists' you'll be able to access your saved citations and export them.