SeaDAS VA 6.3 supposedly comes pre-installed on Ubuntu 10.04 (http://oceancolor.gsfc.nasa.gov/seadas/seadasva.html) but I can't find it. Can someone please help me?
I've read that web-page. I think you have misunderstood. The application is installed in the virtual appliance which uses xubuntu as its default O/S.
The virtual appliance is intended to be run in vmware player under windows - although I suspect if you install vmware products in ubuntu, the virtual appliance will equally run in ubuntu.