According to this Register article, Oracle has cancelled HP’s OEM contact to distribute, sell, and support Solaris on HP Proliant x64 systems.

From HP’s notification:

As you may have heard, Oracle has exercised its right to terminate HP’s Solaris technical support agreement. If you have purchased Solaris 10 Subscriptions and Software Technical Support for HP ProLiant servers from HP, then you will continue to receive subscription support from Oracle and technical support from HP for the period of your contract. You will be able to purchase 1 and 3 year Solaris 10 Subscriptions and Support from HP until July1, 2010. No renewals will be accepted after this date. HP will deliver technical support through June 30, 2013. After that date, HP will no longer be in a position to provide Solaris technical support.
Additionally, starting with ProLiant G7 servers, HP will no longer certify and support Solaris on ProLiant. Solaris certified and supported ProLiant G6 servers will support up to Solaris 10 10/09 or Update 8 for the standard hardware support period (5 years from the date of shipment).

Oracle’s OEM agreement for Solaris on Dell hardware remains in effect.