Arduino sketch for programming pic controllers.
If you would search the internet you will find quite some DIY pic programmers. However, those designs often either require a true serial or parallel port instead of an easily available USB port or are designed around a pre-programmed controller assuming access to a programmer.
A compelling alternative would be the use of an Arduino as in the ArdPicProg. Load the Arduino sketch, the host program and add a prototype shield with a very limited number of additional components to build your pic programmer. This programmer features also a ICD connector and an RJ-11 jack (ICD2) interface. The complete project including hard- and software is open source and is released under the GNU General Public License Version 3. You can build your own ArdPicProg by using the available kit or especially designed PCB.
The complete setup and the application of the ArdPicProg is described in more detail on http://www.pikoder.com/ArdPicProgEN.htm.