Sun tells me:

  For many years both Solaris x86 and Linux have used the same fdisk
  partition id of 0x82.  Solaris uses that identifier to allocate disk
  space which is then further subdivided by the Solaris VTOC (Volume
  Table of Contents) and Linux uses that id as the identifier for its
  swap partition.

  The new release of Solaris should be out early next year. Solaris
  will begin using a partition id of 0xbf.  We will continue to support
  the older partition id value of 0x82 for compatibility reasons.

  Solaris's fdisk program has been enhanced to allow system administrators
  to switch back and forth between the new and old identifier without any
  loss of data.

So, this may be useful to some people a few months from now.