you could take a look at http://cplusplus.com/
it's a pretty good place to start, the site's got a forum dedicated to Unix/Linux programming where you can get help if you're stuck. For an IDE, you could use Eclipse, vim(yes, some see it as a whole IDE for its advanced features, but it requires a bit of learning itself), Codeblocks is nice, you could even use KDevelop (KDE's IDE) or QtCreator (yes, it could be used as an IDE without using qt libraries at all). The other useful thing is the man pages, section 3 which contains documentation about most useful functions for POSIX systems. Ofcourse, if you need more help, there's always the Programming section here at LQ!