There is a line from the movie Star Trek V, The Final Frontier that I think is very parallel to the situation between SCO, IBM, and the development of the Linux kernel. In an otherwise medicore movie, there's this one scene where Capt. Kirk cuts to the heart of all of the philosophical debate about this being called God the officers of the Enterprise have just met.
In the CNET story just posted on Linux Today, McBride indicates that there is indeed source code alledgedly copied from UnixWare into the Linux kernel. This appears to be a major component of their lawsuit against IBM, as they further indicate that IBM was the one who had access to that code and plagarized it into the Linux kernel.