Step 1: An extremely brief history of the PICkit2
In addition to working with Microchip's MPLAB IDE as both a programmer and debugger, Microchip also created a nifty standalone software for the device which is very easy to use. There is a Widows GUI version and also a command line version of the programming software. The engineers even added a "programmer-to-go" functionality, which allows the PICKit2 to burn chips with no computer at all. So even though the PICKit2's MPLAB debugger is painfully slow, all those other features are quite useful for low volume batch programming on a budget. So even though I celebrated the PICKit2's 7th* birthday by buying an ICD3, it will never make my PICKit2's obsolete.
Step 2: An extremely brief history of PICKit2 clones
Many hobbyists stripped down the programmer to the bare essentials. Other commercial variants were made with robust ABS cases and a more secure RJ-12 connector. One version looks more or less exactly like the original from the outside, and it sells today for around 20 dollars!
The schematic is viewable at this link. Scroll down to page 81-82, or click on "Appendix B: Schematic"