I was able to install Aptana with no issues on Feisty 7.04. I wrote a quick How to on the Aptana forums. Obviously as you all know in the new Feisty repositories the Mozilla and libswt3.1-gtk-java seem to be missing. This can be solved by simply grabbing them from the edgy repositories. It creates no conflicts and everything is seamless from there. Here's how I did it.

Edit /etc/apt/sources.list by issuing the following command

sudo gedit /etc/apt/sources.list
insert the following

deb http://ubuntu.mylemontree.com/packages/ aptana-beta/
deb http://de.archive.ubuntu.com/ubuntu/ edgy universe
Then run update by issuing the following command

sudo apt-get update
Now run

sudo apt-get install mozilla libswt3.1-gtk-java
Now you can install Aptana as the required dependencies will have been met

sudo apt-get install aptana
*orignal post