Sweet! HTC has posted their Windows Mobile 6.1 upgrade for the Touch Cruise. The upgrade is a generic ROM, which means it lacks any carrier customizations and is thus targeted at the unlocked version of the Touch Cruise. However, from the instructions, it looks like it will install just fine if you don't mind losing those carrier customizations. There is no US carrier branded Touch Cruise, so no worries if you bought one in the US.
The upgrade also includes some significant bug fixes, which are outlined in somewhat awkward English on HTC's download page.