Antonio,
You can get both sun and ALPHA/OSF1 binaries and a great
user interface for GRASS4.1 from the following;
Osiris Systems Corporation
8846 Carmanah Terrace
Sidney, B.C.
Canada
V8L 5E9
Phone: (604) 655-4484
Fax: (604) 655-4411
Internet: daryl@osiris.com
If you would like additional information I would be happy to pas it on!
Daryl