For the last, hmm, 6 months I\'ve been reading into Programming in C, I got myself K&Rv2, BEEJ\'s socket guide, Expert C programming, Linux Systems Programming, the ISO/IEC
Consider reading more content on the "concepts" of programming than purely syntax:
Join a mailing list/newsletter/magazine/podcasts for programmers in your area of expertise: http://www.drdobbs.com/cpp/;jsessionid=XVZEO0SKOCRRBQE1GHPCKH4ATMY32JVN
Visit StackOverflow.com and try to solve issues periodically to give yourself a mental challenge and help others.