The Qt3 book already mentioned is a MUST HAVE (I even PAID for it!) (They even had it at Barnes and Noble!)
of course when I got it Qt4.1 rc 1 was already out (and I wasn't going to start using an old version!) so I pretty much used it to just get an idea about HOW to use Qt since some of the syntax is a little different.

C++ In Plain English is a great reference book, especially for people moving from 'plain old' C to C++. (Which I did kicking and screaming, BTW and now would never go back) It touches on many topics but puts a lot of focus on object orientation and skims over things like int,long,float,printf,arrays,etc (eg. things you should already know unless you are completely new to this)

Not a C++ book, but the O'Reilly Pocket Reference on Regular Expressions is quite helpful even though it is REALLY meant for Java, C#, and PHP

Katrina