Although Microsoft still refuses to admit that it exists, the first Service Pack (SP1) for Windows Vista is definitely on its way. Currently in beta testing, SP1 will include fixes for many of the bugs discovered in the new OS since its launch last year.
So what can we expect from this new Service Pack? The most visible change will probably be the way the built-in desktop works if you install desktop search from another provider (like Google or Yahoo). Microsoft have had to correct this behaviour after complaints from competitors. Otherwise, SP1 will mainly consist of bug and security fixes, many of which have already been released. Also likely to be included is an update to the Vista kernel (the core of the OS) and changes to the Kernel Patch Protection element to allow anti-virus products to work more closely with Vista. More detailed info on the coming chages can be found at Paul Thurrott's excellent Windows SuperSite.
While no roadmap has been officially announced it looks likely that Vista Service Pack 1 will be released at the beginning of 2008. It's also expected that XP Service Pack 3 will be released at around the same time. In the meantime, we'll keep an eye on reports from beta testers for any more juicy morsels of information.