I ported some NRF24l+ library long time ago but was having lot of problems with it trough time, it was not easy to use and had some conceptual problems that could only be solved by a complete rewrite so I looked around and found a very well written library for NRF24l+ made for Arduino so I decided to port that one too. I'm very very very happy with how this one works, porting was not a lot of work so .. here it is if anyone wants it available for free at source forge xc16 nrf24l+ library page (http://http://sourceforge.net/projects/nrf24l-xc16/)
Here are also the original Arduino library getting started link (http://http://maniacbug.wordpress.com/2011/11/02/getting-started-rf24/) and original arduino lib github page (http://http://maniacbug.github.io/RF24/index.html) as this guy (manicbug) did all the work, I just converted his C++ code for Atmel into C code for XC16 microchip.