need help with system speaker control in c

Hopefully no one will be too mad at me because I accidently posted this in the software forum too and can't figure out how to delete it...

I can't find much help on the internet about how to control the system speaker on a computer. I got some help from this site which explains that you have to first send a "PIT comtrol word" to 43H then a counter value to 42H and finally to turn on the speaker by turning bits 0 and 1 on at 61H.

So, I sent B6H to to port 43H as given in the example. I'm really confused as to what this does. I then send some number to 42H and the number 3 to 61H. I know this will turn off all other bits at port 61H besides the last two, but it works anyway. Here is what im pretty much doing in C:
outportb(0x43,0xb6);
outportb(0x42,12);
outportb(0x61,3);
I get some sound out but I'm a little confused as to why this is happening.

my two major questions are:
-what does this "PIT control word" mean?
-is there any table i could look at to see what number means what note when sending something to 42H?