[shifferman99]

ok, found the culprit - if you're using the default windows mobile dialer skin (the one with the green/red buttons on screen) - your volume control won't change as you press the volume buttons when on a call, whether you're using your speakerphone or your earpiece. BUT ~~> when/if you're using the HTC dialer skin (the one with the white buttons and the big red "end" button that most of you fine people are probably using 'cause that's how the touch pro comes stock), then you have no problem with changing the volume as needed while on a call with the appropriate side buttons.
BTW, if you want to try and switch to the default windows mobile dialer skin I was referring to (which I think is more useful, but that doesn't matter now 'cause the volume buttons don't work with it), you can go to:

'HKEY_LOCAL_MACHINE / Security / Phone / Skin'
change the value of 'Enabled' from 1 to 0.
soft reset

The funny thing is, the HTC dialer skin in fact takes a bit more memory than the windows mobile skin, so if you grow fund of the default windows mobile skin, you will actually save some memory while you're at it...