Solaris 10 includes almost 200 open-source packages certified by Sun. It is also supposed to be linux-compatible. Sounds like that work is partially complete in the current version of Solaris 10, and will be improved on with the "Solaris Linux Application Environment" in later releases. Here is a quote from Sun's website, for more info go to
www.sun.com and click the Solaris 10 link.
What interoperability features are built into Solaris 10?
Solaris 10 offers a number of Linux interoperability features including:
Seamless interoperability between Solaris and Linux-based systems
Built-in binary and source code compatibility
Easy portability with Java technology
Sun Java Enterprise System software for standardized Java technology-based network services
Integration of key open source applications
Free, high-quality porting tools
Common desktop environment with Sun Java Desktop System desktops
Designed for compliance with the Linux Standard Base (LSB) specification
What's happening with Solaris and Linux Interoperability?
The Solaris Linux Application Environment, which enables users to run Linux applications natively on Solaris, will be delivered in a Solaris 10 update.
Based on the overwhelming interest received from customers, Sun plans to extend the development of these technologies and work with selected customers to determine the best design and delivery vehicle for this feature. A second technology preview, based on further development of the Solaris Linux Application Environment, is expected to be available later this year.