The $20 2-port PCI USB 2.0 controller I picked up from CompUSA works fine without any configuration at all in my Ultra 60, under either Solaris Express or the latest OpenSolaris build:
Jun 21 15:34:23 bradford pcipsy: [ID 370704 kern.notice] PCI-device: usb@5,3, ehci0
Jun 21 15:34:23 bradford genunix: [ID 936769 kern.notice] ehci0 is /pci@1f,4000/usb@5,3
Jun 21 15:34:23 bradford pcipsy: [ID 370704 kern.notice] PCI-device: usb@5, ohci0
Jun 21 15:34:23 bradford genunix: [ID 936769 kern.notice] ohci0 is /pci@1f,4000/usb@5
Jun 21 15:34:23 bradford pcipsy: [ID 370704 kern.notice] PCI-device: usb@5,1, ohci1
Jun 21 15:34:23 bradford genunix: [ID 936769 kern.notice] ohci1 is /pci@1f,4000/usb@5,1
Jun 21 15:34:23 bradford pcipsy: [ID 370704 kern.notice] PCI-device: usb@5,2, ohci2
Jun 21 15:34:23 bradford genunix: [ID 936769 kern.notice] ohci2 is /pci@1f,4000/usb@5,2
Jun 21 15:34:24 bradford usba: [ID 912658 kern.notice] USB 2.0 device (usb46d,c03d) operating at low speed (USB 1.x) on USB 1.10 root hub: mouse@2, hid0 at bus address 2
Jun 21 15:34:24 bradford usba: [ID 349649 kern.notice] Logitech USB-PS/2 Optical Mouse
Jun 21 15:34:24 bradford genunix: [ID 936769 kern.notice] hid0 is /pci@1f,4000/usb@5,2/mouse@2
Jun 21 15:34:24 bradford genunix: [ID 408114 kern.notice] /pci@1f,4000/usb@5,2/mouse@2 (hid0) online