It had been a while since I had updated SQL Developer. It turns out that version 2.1 was released March 1st of this year. I've downloaded it and created a Debian package. It can be downloaded from the Bit Badger Solutions Linux Software Repository.
I've used it with Sun's Java 6 Update 18; I have not tested it with OpenJDK. If you have problems getting it to work, you may want to check the previous post on this topic.