PIC16F84A is unjustifiably expensive, but it will work for you, it is the flash version (upgraded) of the 16c84...
MPLAB can take your asm program and convert it to the pic16f84a's machine language. Make sure you select which device you are trying to develop for, it is important so that it can assign the correct registers.
asm programming is in my opinion slightly easier and far more versatile than basic, so good choice. However, for very advanced design you will almost certainly need to use C.. I'm working on a C++ compiler for PIC Micros... I'll be excited when I'm completed!
You can use so many different ways of actually loading the hex into the PIC. I recommend buying a USB one from melabs they are cheap and can program almost all of the PICs in existance. Alternatively, microchip has some on their website, and there are also industrial tpyes that can program in 1 second to 16 chips at a time...costing about 800 dollars. Well worth it in the long run if you mass produce your designs.
Sincerely,
Jesse Randall
Electronic Engineer
**broken link removed**