[Messenjari]

Depends on what version of Photoshop u got....If u have 5 *like in the image u have* its right there as a check box....but if u have 7 or higher...its on the layers window as well but it is a little white Box shape Button with 4 little squares in it put ur cursor over it and it should come up as "Lock Transparent Pixels"

As for the Brushes U can go to: Window -> and then Click "Brushes"
and when u go to use this window u must be using the Brush tool as ur looking at that window or else it will be all grey as for the other window u are describing (thats above the Brushes option) i dunno u_u cause i have Photoshop 7.0 if u have 7.0 its all combined into that brush window as well....if u have 7.0 then woohoo

Hope that made some sence