Yesterday Microsoft released the first service pack for the Office 2007 suite. I've installed it on a few systems and everything seems OK ... so far.
SP1 for Office 2007 seems like a typical service pack in that it's a collection of bug fixes and optimizations tweaks rather than an update that brings in new features or changes user workflow. The Office 2007 suite SP1 is 220MB in size and installs in a few minutes. It requires a reboot after installation but after that there's no sign that it's been installed unless you look at application version numbers.
I've rolled SP1 out of a few systems and the process seems painless. So far everything seems to work pretty much as it did before and I've not run into any unexpected tar pits.
So far the only way to get Office 2007 SP1 is to go looking for it yourself. Microsoft isn't expected to push SP1 through the Automatic Update channels for three to six months.