Now both MPLAB and HI-TECH have been replaced by the MPLABX IDE and the XC8 compiler but that doesn't mean you can't use the MPLAB and HI-TECH to learn C programming. They still work just fine. They just don't support any new components that may be released in the coming years. At some point I plan to update the books but there are many schools using my books to teach C programming. So here is a link to the archive where you can still download the MPLAB/HI-TECH combination installation files.
MPLAB 8.30 - HI-TECH v9.60PL5
MPLAB 8.56 - HI-TECH v9.71A
MPLAB 8.60 - HI-TECH v9.80 <-------
MPLAB 8.70 - HI-TECH v9.81
MPLAB 8.76 - HI-TECH v9.82
MPLAB 8.80 - HI-TECH v9.83
MPLAB 9.83 - HI-TECH v9.83
I recommend this for the books since HI-TECH made some changes after this that are not reflected in the book's code samples.