0x has been in the works for a while, and adds a number of things already in the Boost libraries. it will be nice, but seems to keep getting pushed back.
i believe the GNU compiler has an experimental 0x branch if you want to try it out now
Visual C++ already supports a subset of the new standard, including the nullptr keyword and lambda functions. I'm really looking forward to std::thread.
At least the Techical Review 1 (std::tr1) is widely used already, and it is a part of the upcoming standard. Shared/weak pointers (the main thing I've widely used from tr1) are really nice when you get used to them
