I never had any trouble at all learning C++ after learning C. There were no new concepts that I can remember. Objects & classes? Basically, if you can use a struct, then you can use an object/class. Admitted, the transition from using printf() to cout took a LITTLE getting-used-to, but the only problem I really had was that I kept trying to write it like this:
cout << "blah, blah");
I just had that "bad" habit of tying the '')'' at right before the semicolon (either that, or, due to 11 years in lit classes, I''d try to end it with the semicolon INSIDE the " and "). In any case, I''m currently writing Pong in the Windows GDI (which I''m going to learn DirectX and then add a little of my own flavor to the game), and I''ve used nothing BUT C. I understand, I''ll have to change to C++ to use DirectX, but other than using DirectX for I/O, the game logic itself is all pure C. And, of course, until I get to the point that, from any standpoint, it would be better to use classes (member functions! Yay!) instead of structs, I will continue to use C until I die.

BTW, to learn C, I read C for Dummies Vol. 1, but then the only way I could find Vol. 2 was in a package WITH Vol. 1, wich I didn''t want to waste the money on two copies of the same book. So...I went out and bought Teach Yourself C in 21 Days (I had a good time with Teach Yourself Java in 24 Hours...which may be why the C-C++ transition was easy for me--I already understood OOP), and read through that, then I bought Teach Yourself C++ in 21 Days, and read through that (I was also able to simply skim over the first week, because most of it was review from C). I would highly recommend both of those books...although I HAVE only been programming for 4 or 5 months now (and I''m well into Win32 API, and I''ve already learned to hate/fear MFC).

P h a n t a s m
"Through dreams I control mankind."
--Legend