Quoting from the Novell official announcement:
Novell today also announced the commercial availability of the SUSE Linux Enterprise Virtual Machine Driver Pack, a bundle of paravirtualized network, bus and block device drivers that enable unmodified Windows* and Linux* guest operating systems to run with near native performance in virtual environments created with the Xen* hypervisor technology integrated in SUSE Linux Enterprise and Intel* Virtualization Technology and AMD* Virtualization hardware.
The Virtual Machine Driver Pack includes drivers for Windows XP, Windows 2000 and Windows 2003, and will ship in July. Drivers for Red Hat Enterprise Linux 4 and 5 will be released later this summer and will be added to the driver pack at no additional charge via maintenance update. A one-year subscription to the Virtual Machine Driver Pack will cost $299 per physical server for up to four virtual machines or $699 per physical server for unlimited virtual machines. Xen drivers for SUSE Linux Enterprise Server are already available and ship as part of the SUSE Linux Enterprise distribution.
So after XenSource and Virtual Iron, Novell is the third company trying to raise some direct profits from Xen distribution. Company partnership with Microsoft is critical from this point of view, indirectly implying Novell drivers will perform better than ones provided by competitors.