Many developers seem to think that until the spec is released, there won't be any support. That's just not so. Some of C++0x was in Visual Studio 2008 "Feature Pack". More was in VS 2010. Still more will be in the next one. Informed opinions guess that a beta or CTP of "vNext" will be available in mid September, to coincide with the BUILD conference Microsoft is holding. It's just speculation, but it makes sense. Microsoft has said publicly there will be a "large C++ presence" at BUILD.
Perhaps some corners of the spec won't be implemented for a long time. Your definition of "complete" may be more stringent than someone else's. To see where things stand at the moment, use this table from Scott Meyers: http://www.aristeia.com/C++0x/C++0xFeatureAvailability.htm - there are tabs across the bottom for language features, library features, and so on. I expect Scott will keep this up to date as compilers release new versions. For now, you can use it to guide which features are "safe" for cross-compiler work.