There is now a single menu option to handle adding things to Sparks!: Action > Subscribe, Record or Import.... You'll also see this dialog when you drag a URL to Sparks!

You'll note a few things here:

• Everything to do with adding things to Sparks! is here: adding radio stations, adding weblogs and podcasters, and adding OPML directories.
• The menu items are greyed at different levels: Sparks! tries to determine what the best action for the URL or filename you've entered. If you've entered something that's clearly incompatible with an action it will be inactivated (the icon will go grey too) — for example, trying to add a file as a weblog.
• There's three extensions at the bottom of the list: Send to Del.ico.us, Send to Movable Type Weblog and Send link via e-mail. What these do should be fairly self-evident, but we'll explain further in an upcoming entry.

  Extensions are shipped as source code and it should be fairly easy to add new extensions yourself if you know a little Python.