I really like the online STL documentation provided by http://www.cplusplus.com/.
Separately, I use some of the TR1 extensions via their Boost implementations.
I would like to find TR1 documentation online which is as good as the standard STL documentation provided by cplusplus.com. I'm especially interested in smart pointers and the hash based containers like unordered_set / unordered_map.
Currently I'm using Boost 1.34.1 on Ubuntu 8.04, but will be moving to whatever version of Boost is on Ubuntu 10.4 sometime in the next few months.
I haven't had much success with the Boost 1.34.1 documentation so far. I'm assuming that the best ( most portable ) way of using TR1 extensions is via Boost.
Edit
I figured out why I was having problems with the Boost 1.34.1 docs; that version of Boost doesn't include hashed containers in it's TR1 implementation.
Hashed containers only started being included in Boost's TR1 since version 1.37.0.