Author's reply concering that:

Back when I made that post I thought it was an 8253. But I checked the sources for the function that Beep.Sys uses to program the timer and it claims that it’s an 8254 so I went with the source code.

How hard would it be to use the chip? Not hard but now that Win7 has shipped, the number of machines with an 8254 that’s actually wired to something is going to dwindle to around 0. The machines will still have an 8254 (it’s on the SuperIo chip in every PC) but it won’t be connected to any hardware.